Jul 29, 2020
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Weighted Blanket Design and Thermal Comfort Comparisons

Learn how to objectively compare weighted blankets using the scientific principles behind their designs and materials!

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The misinformation about product comfort properties across the whole bedding space (this doesn’t just pertain to weighted blankets) makes buying a weighted blanket a confusing ordeal. In efforts to maximize their own demand, many retailers will advertise their blanket as having comfort properties that do not even pertain to the materials used inside their product. For example, fabrics like Minky are continually advertised as being ‘cool’ and ‘breathable’ fabrics while their material properties make them one of the warmest, un-breathable fabrics on the market today. Minky is a plastic polyester fabric that is made out of old-world polyester. (‘Cool’ Minky is a micro-polyester)

In order to tell what a weighted blanket common flaws are, look at all the negative reviews of products across ALL brands in the market. As a result of researching consumer complaints, most brands have been trying to market their products as helping with the highest frequency complaints in the space: a) lack of pressure application, b) cover / duvet incompatibilities, c) lack of thermal regulatory control, and d) durability concerns. Typically, most business owners try to capitalize on these unmet needs through marketing tactics where their product shows up to consumers who search based on these needs, not by improving the product to fill the need itself. Thus, you have many products that advertise to fill a need, but may not do a good job. Reviews are also commonly made up and skewed in the market. It’s up to you to look around the market and avoid commonplace market deception. The majority of brands out there mis-advertise their products.

truHugs Quick Tips: Comparing different weighted blanket products on the market

Our goal in writing this post is to help you make the best-weighted blanket purchase decision possible. Its a pretty long read, but we are pretty sure you will find all the information highly relevant and concisely summarized. The first half of this article introduces you to the concepts of material science and weighted blanket product design. Then, we jump deep into our summarized findings of the thermal regulatory aspects of weighted blanket cover materials.

Executive Summary

Weighted blanket product design comparison summary

Weighted blankets that have smaller grids apply desired pressure better than weighted blankets with larger grids.

Weighted blanket covers afford ease of maintenance, however, many covers have intrinsic design flaws. Designs with more ties are better than fewer ties. Designs, where the cover is attached to the blanket via a zipper, will have hardened areas around zippers that may irritate the neck. However, they also detach faster. Covers made from 2 materials may inconveniently drag during re-adjustment due to surface friction incompatibilities, causing eventual tie breakage.

Fluffy weighted blankets apply better pressure, reduce noise during weight adjustment, and absorb shock better. Fluffy weighted blankets are warmer than non-fluffy weighted blankets, assuming the non-fluffy weighted blankets don’t have scrims supplementing their surface fabrics.

Weighted blanket fabric thermal regulation comparison summary

The breathability of a weighted blanket is the most important factor in providing continuous thermal regulatory comfort throughout the night. High breathability values allow the heat unconditionally released from the body to escape by cycling air between the environment and beneath the weighted blanket. Regardless of your unique context, lack of breathability inevitably results in increased trapped hot air, which eventually leads to sweat and awakening. The only variable here that is unique to each of us is time. Thus, more breathable weighted blankets are more thermally ‘flexible’, regardless of an individual’s personal characteristics or context. That is, less breathable weighted blankets cause overheating to occur at faster rates regardless of ambient environmental temperature or an individual’s innate metabolism.

Fabrics are a key component that can limit or help breathability. Controlling for confounding variables, the following weighted blanket fabric materials are listed from most thermally ‘flexible’ to the least: Lyocell >> 400TC Cotton (which 200 TC cotton is commonly misadvertised as, read below for more) >> Micro polyester >> Bamboo viscose >> 200 TC Cotton >> 233 TC Cotton >> Polyester. This is assuming no scrims are implemented, which are frequently found in integrated / 7 – layer designs. Thermally ‘flexible’ fabrics can provide additional comfort to hot sleepers, people living in warmer humid environments, and those that live in environments where the temperature fluctuates greatly throughout days or seasons. (like in the Southwest desert).

Breathable weighted blanket fabrics cannot also be “cool to touch”. These two characteristics are ‘inversely’ related in all fabrics, natural or synthetic, because of fundamental scientific principles. Most “cool to touch” fabrics in the market have minimal breathability. Thermal comfort is a weighted blanket feature that is the most commonly misunderstood in our space.

Comparing the three fabrics used in nearly all affordable weighted blankets…200TC cotton, minky, and the elusively outdated 233 TC….minky has superior thermal regulation because of the way 233TC cotton fabrics are often finished with an unbreathable film to decrease weighted bead leakage and 200 TC cotton fabrics have to be backed by a scrim. Between 200 TC and 233 TC wholesale cotton, 233 TC fabrics are worse, because breathability is completely limited. Quality, thermal flexibility, and prices vary drastically among synthetic fabrics, so make sure you don’t buy a weighted blanket with cheap imitation Minky.

If you already own a weighted blanket, you can test its breathability at any time by holding it to your mouth and blowing through it. If no air comes out on the other side and you are waking up to sweat, better solutions are available.

How to use this post to make a purchase decision

Post formatting and updating schedule: This post is in long-form and may be separated into separate topic posts in the future. We will continually edit and revise this post until we feel like the topic of cover fabric thermal regulation is covered in full. Use the table of contents to guide yourself to your own unique topics of interest.

We start easy with self-evaluation practice scenarios to solidify learning then dive deep: We only summarize product design to ease you into understanding the main technical topic of this post, our ‘harder-to-understand’ material science analysis of weighted blanket fabric thermal regulation characteristics. Appropriately, we have used the framework of lower-cost versus higher-cost designs to help introduce fundamental product design concepts. This is perfect because, during this initial learning phase, you will have many real-world examples to apply the concepts towards as we explain them. Please note, we have no bias towards higher-cost designs and your needs are your own. Even when we say higher quality, it is biased, because we like fluffy breathable weighted blankets ourselves, whereas you might not!

It’s up to you to do your own due diligence, including comparing us! Tell us how we can improve!

Then, once you are warmed up to material science, we will go deeper into a specific part of a weighted blanket…the fabrics they use and how they affect your thermal comfort. This is a more advanced section that we summarized the results of above.

Please feel free to jump around to your topics of interest using the table of contents. You have the freedom to read or not read, whatever you want.

Appended update notes: February 17th, 2019 (Re-organized sections, further editing & peer review); February 16th, 2019 (BGR); February 15th, 2019 (comparing lyocells added to limitations); July 25th, 2019 (updated conclusions and analysis to be reflective of updated knowledge); August 23rd (updated flow of article, submitted for peer review)

How a weighted blanket’s price affects its comfort

Your thermal comfort is primarily the cumulative byproduct of the types of materials layered inside your weighted blanket. This includes all the fabric layers used, the batting used (fluffy filling used), and the weighted filler used.

In some instances, brands (like ours) may include a cover. You may think that stacking two materials in parallel may inevitably make your blanket hotter. That makes for some good common sense but is that really true?

Multi-layered fabric assemblies in low-cost designs

Thermal comfort is a byproduct of the material and design properties of several layers inside your weighted blanket

Really, when you only buy a weighted comforter without a cover, your experienced thermal regulation comfort will be limited by the singular material used than if you buy a weighted duvet with a duvet cover. This applies to the first 10-15 minutes of when you first lay down and ensuring proper temperature control until you wake up.

As an example, let’s say you are lying on your bed with a single fabric in the form of a linen sheet over your body. The heat escapes through the linen into the air on the other side. Ok, great. If you had a cotton sheet or another blanket on top of the linen sheet, it would continue to absorb the heat and moisture transmitted from the linen sheet. This multi-layer framework allows a “blanket engineer” to preserve the tactile properties of linen while allowing you to gradually reach a higher average level of warmth by adding cotton behind the linen. Without multiple layers, you may get too hot or too cold at a rate that decreases your overall sleeping comfort.

In a weighted blanket, the heat released from your body warms the air between your weighted blanket and the bed.  This warm air is either released through the edges of a blanket, where there are cracks…like when you sleep with your feet out or has to diffuse through the blanket.  If cycling air has to diffuse through the blanket, it usually has to go through…layer 1 – a weighted blanket cover fabric -> layer 2 – a weighted blanket inner fabric -> layer 3 – a polyester scrim (optional -> layer 4 – batting -> layer 5 – another polyester scrim (optional) -> layer 6 – the other side of a weighted blanket’s inner fabric -> layer 7 – the other side of a weighted blanket’s cover.  Implementing any of these layers with the wrong materials or components may decrease thermal flexibility by creating a thermal bottleneck.

Low-cost fabrics = low-quality fabrics = lower overall weighted blanket thermal flexibility because of the way low-quality fabrics have to be processed and reinforced to maintain acceptable durability

While more affordable weighted blankets sold without a cover may have multiple sheet layers, many of these layers are often implemented with the goal of supplementing the weak durability of thin superficial cover fabrics and protecting against bead leakage, not to control for thermal regulation.

The yarns of most low quality cotton fabrics need to have a stiff corn syrup applied immediately post spinning just to maintain structural integrity. Otherwise, they break apart more frequently because they are made from the “left over” fiber fragments at a fiber mill…which are often filtered from higher quality fibers at the beginning stages of raw fiber processing. Later on, during fabric finishing, another film is sometimes applied that makes the fabric even more rigid and impermeable to air.  This film was initially implemented and still is today with the goal of preventing bearding and glass bead leakage, two durability issues that were so prevalent back in 2016.

– truHugs Insider Secrets: Upstream insights and experiences.

Scrim = lower overall weighted blanket thermal flexibility via slower diffusion of air

In addition, thinner superficial natural fabrics are often supplemented with polyester scrims, another layer added with the good intentions of reducing batting and weighted bead leakage.  Scrims decrease thermal flexibility and increase overall weighted blanket rigidity as negative side consequences.

A polyester scrim (as used in weighted blankets to prevent leakage) is usually a solid piece of rigid air impermeable ‘vinyl’ with hundreds of little holes usually about 1/32th to 1/16th of an inch in diameter spaced about a 1/3rd to a 1/4th inch apart. After hot air passes through a surface fabric, it inevitably ends up trapped between the scrim and the surface fabric. The hot air is then bottlenecked trying to diffuse through the small holes in the scrim. More movement is often required from the user (via tossing and turning) to generate air pressure that has to pass through the superficial natural fabric layer and push the hot air trapped between the scrim and the superficial fabric layer through the scrim’s little holes…as the scrim vinyl itself is completely air resistant. This sequence of required thermal diffusion in integrated designs definitively decreases a weighted blanket’s overall thermal flexibility, but to a less exaggerated extent for sleepers that toss and turn more frequently. ‘Active’ sleepers generate more natural air pressure during sleep than sedentary sleepers because they cause the blanket to be subjected to increased air pressure every time they move.

– truHugs Quick Tips: Common real world examples to help you learn.

For these firms, the prioritization of cost reduction which is primarily achieved by decreasing product quality also applies to batting and gridding.

If you already own a weighted blanket, one way you can tell you bought a weighted blanket with low thermal ‘flexibility’ is to hold it in your hand and blow through it.  If no air comes out the other side, your thermal comfort was sacrificed with a focus on reducing the blanket’s raw material costs.  Scrims can be felt by pinching the surface of your weighted blanket or by varying ‘blowing’ force intensity while examining how much hot air is trapped or comes through the other side.

An unbreathable fabric finish that is often found on 233 TC fabrics can sometimes be differentiated as an unnatural dull “plasticy shinier-than-normal” sheen which represents the coating applied. This visual tell is often supplemented with unnaturally ‘rigid’ surface fabric wrinkling. Of the affordable cotton weighted blankets on the market, ones without a sheen are better…even though they are usually backed by a polyester scrim.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Gridding and batting for weighted blankets, not baseball

Gridding dimensions are important

Weighted blankets that typically lie in the price range of $50 to $110 are more affordable but they may be less comfortable while lacking the pressure boosting benefits of weighted blankets in the first place.  (lets be honest cost is always a consideration for all of us…if you end up buying one we don’t blame you…life is hard!)

You can tell how big or small different grids are by comparing different product pictures across different brands.  They are all folded relatively the same when presented, but the number of grids you see on the top fold will differ.  Using the number of folds you see, you can estimate what the grid size is for any brand.

truHugs Quick Tips: Comparing different weighted blanket products on the market

The average shoulder widths of American females and males measure out to be 14 inches and 16 inches, respectively. Therefore, it makes sense to us that larger grid designs have a higher likelihood of having the beads fall off your body into its lowest vertical position with the least potential energy, on to the bottom of the grid stitching walls where the weighted grids are in more vertical positions, that is…where the blanket drops off from your body towards your bed.

Exacerbating the lack of weight felt by users is the fact that the weight of an overall weighted blanket is distributed within each gridded compartment throughout the weighted blanket, including the ones on the outer edges not typically over your body. The surface area of most people is less than the surface area covered by ALL the grids (surface area density). What this means is that if you take a 15 lbs weighted blanket, probably about only 7 – 12 lbs is being applied onto your body’s contact surface area at any given time.

Fluffiness = Batting = shock absorption and warmth

Exemplifying batting, we will say that down would be the batting in a down-filled comforter. Weighted blankets that lack voluminous batting to lock weighted filler beads are designed to maximize how fast heat can dissipate in extremely hot environments. This coolness factor is often implemented by manufacturing low cost weighted blankets with less insulation material (aka batting). As a byproduct, lower raw material costs (due to extremely low amount of batting materials used) result in lower prices.

Batting thermal regulation is a very advanced topic which has numerous guiding scientific design principles that are opposite that of fabrics.  This is because instead of being one solid sheet of fabric, batting is spun into a less dense matrix consisting of many fibers.  More on batting thermal regulation will be provided later.

Batting provides a fluffy layer so you feel what you expect when you buy a weighted blanket, comforting shock-absorbing fluffiness. Without it, you basically have a bean bag with “weighted beads” shifting around between several layers of thin fabric sheets. These weighted beads are more readily felt in low-cost single-layer cotton shelled weighted blanket designs, which are one of the most uneven and naturally thin fabrics available as a cover material at the time of this writing. One of the highest frequency complaints you will find for these products is the weighted filler is more easily felt by consumers.

Next, we will discuss how batting helps with weight displacement inhibition.

Fluffiness = Batting = less noise and more pressure

With batting, there is less space, the weighted filler beads get stuck in the batting or get pushed up against the stitching walls. Every time the beads want to shift they have to battle the tight narrow corridors created by the batting and grid borders, inhibiting their rate of displacement. As a result, batting helps keep weighted beads vertically higher while slowing their respective displacement rates. The impact of this goes to the point of pushing the weight more onto whatever horizontal body plane might be present, increasing planar friction / pressure felt, and ultimately decreasing the possibility that the blanket will slide off your bed. All these aspects help keep pressure where it’s supposed to be during “activities of daily living” movements.

In order to determine how much batting is in a weighted blanket, look at how ‘fat’ (thick) each of the weighted blanket folds are in its product picture. If the product picture looks super thin when folded up, it probably has less batting. Budget-friendly weighted blankets without batting or larger grids may present their product in orientations OTHER than being folded because their product is not as photogenic when the weighted blanket is folded. Brands that use lifestyle product pictures with models *typically* (this is not a general rule, please review the details yourself) have less batting and larger grids. In this confusing real-world product evaluation example, estimate the size of the model and then use that result to obtain a rough estimate of the blanket thickness and gridding size.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Under-filling is a problem, but so is over-filling

Grid volumes scale directly with grid stitching sizes. Common sense tells us that overfilling grids may result in decreased pressure application, as the blanket won’t follow your body curves like it’s supposed to. Instead, the weighted blanket’s rigidity will reduce the amount of weight applied to your body as the blanket as a whole basically ends up a rigid plank angled towards the periphery of your bed, when the blanket is supposed to wrap the sides of your body.

All these outcomes are reliant on the mechanical properties of the batting itself, how it was prepared (ie. with epoxy glues), and how it works in conjunction with the other sheet layers inside a weighted duvet. Some battings have more ‘drape’ than others, and are more suitable for weighted blankets.

The horizontal planar surface of a weighted blanket is like a bunch of valleys and hills (a continuous wave length when viewed from the side), as the superficial fabric layers have to rise because of the batting and come back down to the stitched lines for each grid. If too much batting is used, you will feel pressure in fewer, more concentrated areas of the body (the areas where the hills are).

The prior mentioned rarer (due to higher material costs) “weighted blanket rigidity” design flaw is far more elusive to the common eye than flaws that result from cost reduction. This flaw can only be seen in the market when the weighted blanket is featured over someone lying on their bed. If you don’t see the blanket drop immediately towards the bed from the highest horizontal body surfaces of the model (ie. a knee) where the duvet grids are supposed to hug your body while being vertically oriented (ie. along your leg), the blanket as a whole unit is probably too rigid to maximize pressure. Using basic geometry, we can conclude that most of the weight in those grids would be supported by the bed, not by your body. Also, look for smaller hills and valleys on blanket superficial surfaces, a sign that overfilling and blanket stitching design issues are not present.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Balancing comfort properties of batting is often ignored

Batting material selection and implementation processes affect a weighted blanket’s warmth, fluffiness, and pressure distribution. Unless batting intrinsic material properties like warmth, loft, retention, and breathability are delicately evaluated with preparation methods, integrated fabric thickness, and gridding size as important synergistic properties of batting comfort outcomes…improving one comfort outcome (.ie such as better pressure application through increased batting volume fill per grids) may have negative impacts on another (excessive warmth). Thus, even though a particular weighted blanket may seem innovative in improving comfort on one factor, make sure improved aspects haven’t worsened others through your own due diligence for the specific weighted blanket of interest.

“Batting volume” / “grid size” ratios BGR is a detailed complex topic we will dive deeper into later as its own separate weighted blanket design discussion category. (don’t forget we introduced it here)

How to address “wallet-friendly” weighted blanket design flaws

Larger grid designs suck for keeping weighted filler beads above your body, reducing pressure felt for the user. Combine these larger grid designs with lack of batting and you have a notable trend of having weighted filler beads slide off your body and onto the bed within their grid compartments, because there is a lot of free space within each stitched grid allowing for rapid dislocation of a greater number of beads…caused by the effects of gravity.

If you already have an affordable weighted blanket or you need to save money, you can decrease the impact of its design flaws by layering the weighted blanket on top of another comforter. This will decrease the vertical ‘drop’ angular curvature to be less severe… that is, your comforter top is more horizontally oriented as a flatter semi-arc shell around the rounder semi-arc outline created by your body.

However, you may still wake up from overheating due to how unbreathable their surface fabrics typically are. *trying the former approach in colder climates or as a colder sleeper may be ok.

If you are looking for an affordable single-layered design that typically lacks batting because of well intentioned budgeting concerns, brands with smaller gridding are better. You need less gridding volume available for weighted filler bead dislocation by having reduced grid volumes because there is nil / low batting fill volume to inhibit movement of weighted filler beads.

Weighted blankets that appear overly rigid will have both a polyester scrim and a fabric with an unbreathable finish. Both these design features increase rigidity and decrease thermal ‘flexibility’ with the added benefit of making the weighted blanket much more durable. An unbreathable fabric finish can sometimes be differentiated as an unnatural dull “plasticy shinier-than-normal” sheen. What you are seeing is how the finishing process changed the superficial appearance of the fabric itself.

Everyone’s priorities and needs are different. Weighted blankets made from low quality fabrics (both in material composition and in preparation) might be particularly fitting for… people on a budget, cold sleepers, people living in extremely cold places, kids, disabled older adults, use as a public throw where only part of the body is covered, or camping. The way they are often constructed in order to overcome their innate shortcomings grants them ultra durability…which is often an outcome that is achieved at the cost of lowered thermal comfort (trapped hot air), softness, and overall weighted blanket drape.

– TruHugs Quick Tips: Insider secrets from upstream.

From a business-oriented cost considerate perspective, you should now know that, in large part, low-cost weighted blankets have their fabrics sealed to the movement of air, which will not help your comfort.  Ultimately, these fabric features were implemented by brands to reduce material costs and return recall, while still being able to maintain the desirable marketing features of the thin natural outer shell which in large part become negligible because of the way low-quality fabrics have to be constructed, finished, and/or supplemented when used in weighted blankets.  (which as you can see are totally different than normal blankets)

Also, we learned that less batting and gridding results in decreased labor costs. This is often done at the expense of reducing felt pressure and fluffy comfort. More batting materials and stitching machine labor time result in higher quality fluffy blankets that replicate the comforters we are all accustomed to while keeping pressure where it’s supposed to be. Unless batting is implemented correctly during product design innovation, many negative side effects “black swans” may occur. (the blanket is too warm, too rigid, etc.)

Now that we briefly covered weighted blanket design considerations from a 10,000 ft “bird’s eye” view, let’s jump into summarizing key weighted blanket duvet cover fabric material science definitions and multiple layered fabric assembly design issues.

How to compare a weighted blanket based on its fabric materials: bridging theory with reality

First, start with the right search terms…which are not the ones that naturally come to mind…

Start with some good key search terms like “bamboo vs cotton thermal regulation”. Maybe you can’t find anything credible. Efficiently, please search a more granular scientific term than the prior term used. An example would be “bamboo vs cotton thermal conductivity”. Please don’t search “bamboo vs cotton coolness” or “summer cooling fabrics”, as all the top results there are made by extremely biased marketing gurus.

Learn the basic terminology

Ok great, you have clicked a link and are looking at your first study. Higher thermal conductivity means that fabric material will feel colder to touch. Increased breathability (aka higher air permeability in scientific lingo) is important for hygiene control and thermal regulation. Maximum Vapor Permeability and Water Absorption is important for sweat management. Handle is how soft or rough a blanket will feel against your skin. Tenacity is how strong and durable your blanket will be.  More information on these definitions can be repetitively found throughout the scientific articles referenced throughout this document, within the “Introduction” and “Method” sections.

You simply can’t have it all

A special note to keep in mind…As you will later learn, higher thermal conductivity values are usually associated with both lower air permeability and water vapor permeability in all the research we’ve read to date. That is, the ability to conduct heat is inversely associated with air/vapor permeability across most fabrics.  Most “cooling weighted blankets” on the market right now advertise they are cooling because they are cold to touch, not because they are breathable.  As you will learn later, breathability is the most important factor to not waking up with night sweats.

The irrefutable “give-and-take” aspects of most fabrics naturally leads into why weighted blanket covers are best bought when the cover material is considered as part of a weighted blanket’s overall design. By using multiple fabric layers, an engineer can take the strengths of each fabric and use them to contribute to overall weighted blanket comfort.

All about weighted duvet covers

The topic of weighted blanket product design in its entirety (even just for thermal comfort, we still haven’t fully elaborated on inner materials, durability, and tactile feel) is so extensive that it can be written as its own book. We will dive deeper and deeper into this topic throughout 2019.

Thermal regulation advantages

Most integrated natural weighted blankets (those with bamboo lyocell shells, bamboo viscose, those with cheap low TC cotton) require a polyester fabric layer underneath it to prevent weighted bead leakage and to increase durability during maintenance.  Trust us, we tried to make our blanket just out of bamboo lyocell and it wouldn’t work.  Thus, most brands advertise their natural breathable outer fabrics while they are really selling a polyester-shelled blanket because the polyester layer is a thermal bottleneck.

Instead, we took the most breathable materials and separated them into a cover.   This is awesome because we provide an extra cover that’s softer than cotton, and its almost invisible thermal regulation wise because it’s so breathable.

Convenience, durability, & maintenance

Different ties and loops in different places

Within the weighted blanket space, each weighted blanket has its own ‘brand’ loop and tie specifications. Buying a weighted blanket separately from the cover may have additional undesirable consequences. Unlike normal duvets and duvet covers, weighted blankets are secured to their covers, usually by up to 12 ties. Tie manufacturing variance in the weighted blanket market ranges typically between 4 ties to 12 ties. Covers with a lower number of ties will have a higher likelihood of becoming unlatched because more force is distributed among fewer ties during movement. At twelve ties, your weighted blanket has 3 times the anchoring security of a normal 4-tie duvet/cover system. Think about the extra weight that is thrown around when you turn from your back onto your side, the cover has to be very securely fastened to split the forces that result from surface frictions between your body and your blanket among ties. If the cover has a different tie system than the weighted blanket you currently have or plan on purchasing, that could be a bad thing.

If you do buy your weighted blanket and cover separately, please make sure that they will work together well.  Brands that use zippers as attachment systems have to use a big sturdy zipper to attach the cover because of the huge forces thrown around during weighted blanket re-adjustment.  These zippers make maintenance quicker and less tedious than tie systems, at the cost of putting a hardened edge around their attachment areas.

The importance of loop/tie radii ratios (LTRR) in weighted blanket multi-layered designs

While bigger tie loops on the inner duvet will increase convenience during cleaning, greater loop / tie radii ratios result in more pull forces from daily movement due to frictional torque generated by the loops on the tie…with the forces originally being caused by shifting weighted filler as your body moves or a hand tugging on the cover. Imagine a tie and a loop, a larger loop would result in more rubbing back and forth, because the anchoring system has more play, with the tie against the inner portion of the loop when the cover is pulled. The tie has more flexibility to move within the hoop during multi-directional movements. Eventually, the tie will become undone.

Ideally… so you don’t have to keep re-tying your blanket… the ties should be have to be slightly squeezed through the loops. Both tie and loop should have appropriate frictional co-coefficients. Ties that are too slippery or small compared to their matching loops will become incidentally undone more often than rougher ties with more width you have to fold. The increased inconvenience of having to manually fold a wider tie through a small loop provides the perfect balanced flexibility of reducing extreme pulling forces by allowing for slippage while maintaining sufficient friction because more surface area of the tie is in contact with the inner loop. With a proper mechanically designed loop/tie system, you won’t always have to open up your cover, reach in deep with your cell phone flashlight, and tie the two in the corner that became undone quicker because thats where you tend to tug on it.

Consumer complaints on flawed tie designs are usually described by unhappy customers in two ways: a) “the inner blanket keeps on becoming unlatched from its cover”, or b) “the weight in this blanket is not properly distributed.” Complaint b) needs to be taken with a grain of salt, because there is high likelihood the user didn’t realize half his ties on one side of the blanket have become unlatched due to improper LTRR implementation. Regardless, the experienced phenomena of tie/loop flaws is present with these reported past experiences.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Always question critical reviewer credibility. Maybe they are just having a bad day.

Balancing comfort versus tie breakage prevention, the importance of cover material surface frictions

Excessive surface friction may damage a fragile fabric with a low abrasion coefficient…making them more prone to tear.  Weighted blanket covers made out of 2 materials may make re-adjustment of the weighted blanket at night harder because one side of the cover will slide quicker under the weighted blanket, whereas the other side has higher friction to slow its movement.   In this case, an unnecessary multidirectional strain is further put on a weighted blanket cover’s ties, causing them to unlatch sooner.

Evaluating consumer complaints on tie breakage is a good way to determine whether the surface frictions between a weighted blanket duvet and its respective cover are compatible. Lack of cover surface friction with its duvet is specifically exemplified by customer experiences that claim “the weighted blanket drags” during readjustment. The surface friction problem is particularly evidenced in cover designs using two different materials, such as the common cool bamboo / warm minky combo. The difference in surface frictions on opposite sides of the cover here causes blanket readjustment issues and cover hang imbalances.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Cleaning convenience during laundering

Washing weighted duvets may damage top-loading washing machines, because of their heavyweight. Metaphorically, imagine throwing rocks in a test beaker and then centrifuging it. Uhm, that has to be bad for the test beaker.

In addition, the popularly used batting inside weighted blankets, polyester/other fabric blends, usually takes a lot longer to dry than their cotton shells. We’ve read many negative ‘review’ reports of weighted duvets taking 2-4 days to fully dry. Although the need to tie and re-tie a weighted blanket cover is an undesirable hassle, the maintenance flexibility afforded by covers will be much appreciated. This facet may be particularly more relevant to people living in multi-story homes. Carrying a 20 pound weighted blanket up and down the stairs is much less pleasurable than carrying one basket with all your clothes and weighted blanket cover inside.

Fabric shrinkage incompatibilities

New micro-polyesters like micro-fleece, micro-plush, and Minky (some Minky is old polyester material) are awesome because they are durable, convenient to maintain, and resist shrinkage. In the modern-day, these fabrics often emulate the heat dissipation and breathability of the cotton. One thing micro-polyesters cannot match is the sweat vapor transportability of cotton.

If the duvet insides are wrapped with an “up to 20% shrinking” cotton shell, the inner duvet will end up much smaller than the outer micro-polyester cover after several washings. Eventually, this will put a strain on the ties to the cover. The functionality will also be severely limited as well as you seek to re-adjust the weight during the night, and you end up with just ‘cover’ in your hands.

The non-shrinking property of polyester is useful for batting (the fluffy filling) in a cotton wrapped blanket. That way, as you wash the duvet the inner filling resists the shrinkage. We should be thankful that most brands on the market with cotton shells have polyester batting (those with batting, some have near none) to counter the shrinkage problem. Not everyone wants the superficial appeal of a vintage cotton-filled weighted blanket. Not to mention the hassle of repairing broken ties.

If batting does shrink in a weighted blanket, you should now know that it will decrease pressure due to increased weighted filler displacement. Instead of filling up the grid volume, the batting becomes this small piece of fluff that fails to serve its original function.

Macs vs PCS

Metaphorically, buying a blanket with a cover from a reputable brand is like buying a Mac instead of a PC. PC often struggles with hardware and software compatibility issues because the computers, in their entirety, were not manufactured by the same firm with software and hardware testing. I must say, PCs are awesome in how customizable they are. Once again, the pros and cons of everything. As a result of the additional research efforts by Apple engineers, Macs reliability generates increased processing efficiency when compared to PCs with the same hardware configuration. These aspects are accomplished by taking complex synergistic relationships between computer software and hardware into account while attempting to maximize computing performance.

Weighted blanket fabric thermal properties that are important to your sleeping comfort

Inner blanket fabric layers should have materials that have higher heat capacities and high resulting heat absorption values to serve as a “heat tank” reserve for thermal comfort…so your blanket, several hours after you laid down, can provide the warmth needed as the night gets colder.

Outer weighted blanket fabric layers should have:

  • higher heat conduction values so they feel cooler to touch
  • high sweat absorption and transmission capabilities
  • softer silkier tactile feel
  • high breathability so air doesn’t get trapped between the blanket and your skin.

All materials throughout the blanket should have comparable levels of breathability so there isn’t any airflow “bottleneck” in the multi-layered weighted blanket configuration creating prevalent, much-dreaded hygiene concerns.

Battle of weighted blanket fabrics that hug your skin: hot or cool?

Here, we will summarize how different commonly found weighted blanket fabric materials affect your thermal comfort. This includes minky, plush, fleece, cotton, and of course bamboo.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

A study called “Comfort and Thermo Physiological Characteristics of Multilayered Fabrics for Medical Textiles” concluded Lyocell was the BEST material to be in contact with a patient’s skin when compared to traditionally used cotton and polyester sheets in a multi-layered fabric assembly. They cite Lyocell as being able to prevent bacterial growth, fungus growth, and the spreading of viruses for hospital sheets. The following paragraph shows how worried they are….

Quote from material science study shows that cotton and polyester are unsuitable materials for hospital environments.
(Mallikarjunan, 2011)

Addressing known confounding factors

The worst part about applying rigorous science methodology is being locked into conventional frameworks that may further delude you from the truth. You think you see more than everyone else, but in reality, you are looking at only 20% of the factors that will influence the outcome. (and its proposed variance). The increased self-perception that you are definitively correct continues to misguide you…you think you have the facts when you only have a minor portion of them. Scientists can spend years developing a false theory that relies on a BS self-perpetuating logical loop. Here, we will state what we did to control for some limitations inherent in material science comparative analysis.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Different types of lyocell lend to similar comfort outcome properties that define lyocell as a fiber in the first place

In the study above, lyocell is defined universally as “eco-friendly cellulosic..new age fiber which unites the advantages of many different fibers.” (Mallikarjunan, 2011) However, other scientific studies point to this article as examining bamboo lyocell when they reference it to support a point they want to make about bamboo lyocell. To double-check this, go to the article and check-in scientific databases what other works have cited it.

What is lyocell?

The Federal Trade Commission defines lyocell as “a cellulose fiber that is precipitated from an organic solution in which no substitution of the hydroxyl groups takes place and no chemical intermediates are found.” Therefore, lyocell is a generic industry term defined in part as a cellulose fiber that results from an organic extraction process. All forms of lyocell, regardless of raw material, are defined as semi-synthetic rayons, as natural raw material pulp is transformed into their respective usable fibers.

Think of raw bamboo or eucalyptus, they are very hard rigid materials. To turn them into usable fabric strands this rigidity has to be broken down, mechanically, or chemically. Therefore, lyocell is taking a natural material, keeping most of its properties, and converting it into useful fibers that can be used to make fabrics through man-made processes. (which make Lyocell even better, as you will read later) This makes lyocell officially half natural (all natural raw materials make up the fabrics) and half synthetic (processed by man to be usable as fabrics).

While merchants of fabrics other than bamboo will continually put down rayons as being non-environmentally friendly, they are referring primarily to modal and viscose variants of rayon, which result in wasteful byproducts during fiber creation. In creating Lyocell, regardless of raw originating pulp material type, all organic solvents are majorly reused and all manufacturing waste byproducts are resold and repurposed.

Going more granularly on the types of Lyocell, there are several types of Lyocell depending on what type of cellulose raw material is used. Two examples are wood Lyocell and bamboo Lyocell. TruHugs ONE uses bamboo Lyocell, not wood Lyocell. An example of a wood that results in Lyocell fibers after organic solvent processing is eucalyptus. Eucalyptus lyocell is branded around the fabric world as premium fabric Tencel, which is trademarked by fabric innovator Lenzing.

How does bamboo compare with wood in making Lyocell fibers that affect your sleeping experience differently?

In terms of the differences between bamboo Lyocell and wood Lyocell, scientists write: “The results showed that bamboo lyocell fiber is similar to the structure and properties of wood lyocell fiber, such as smooth surface, circular cross-section, high crystallinity, high tensile strength, low elongation at break, good moisture adsorption property, and easy fibrillation.”

The similar fiber properties between wood and bamboo Lyocell fibers lead to similar mechanical and comfort outcomes. Material property similarities examples include Lyocell’s: a) definitive soft tactile handle feel, b) thermal regulatory benefits such as supernatural breathability, and c) increased durability. High values of tensile strength are related to Lyocell’s increased fabric durability and the ability to fibrillate gives Lyocell its universal soft tactile appeal…defining comfort outcomes of lyocell regardless of raw material origination.

There is some variance between wood and bamboo raw fibers that result in slightly different comfort outcomes, but the variance is small. Indeed, if you look at the microscopic images you will see how similar bamboo Lyocell and wood Lyocell fibers are visually…. and how different they both are from bamboo viscose.

fibers under a microscope
Look how similar bamboo lyocell and wood lyocell appear under a microscope. They both differ dramatically from viscose.(Yang, 2007)

The authors continue writing, “Furthermore, the bamboo Lyocell fiber surpassed wood Lyocell fiber concerning negative ion effect and anti-bacterial property.” These results may implicate bamboo Lyocell (made from bamboo pulp) may even surpass wood (ie. eucalyptus, birch as raw cellulose pulp materials…) Lyocell in comfort aspects and function as an ideal weighted blanket cover material.

The findings above are cited directly from a material science comparative article published in German journal De Gruyter called “A comparative study of bamboo Lyocell fiber and other regenerated cellulose fibers.”

Picking the most relevant studies

The aforementioned medical textile study will be referenced the most throughout this document to gain some insight. This was deemed appropriate because a lot of the material comparison studies were more about clothing, which results are less directly applicable to helping us derive useful conclusions about blanket textiles. Therefore, it’s important to represent the material characteristics of the samples used for latter comparison.

fabric thread thickness
These are the yarn and weave properties that meet the ‘desired’ minimal standards for medical sheets you sleep on when you go to the ER. (Mallikarjunan, 2011)

Matching fabric weave types

In order to make accurate comparisons, we must choose the fabrics that have weaves most similar to those used in weighted blankets. This study did not compare with a plain cotton weave, the most common type of cotton weave found in weighted blankets today. Bamboo lyocell fabrics are most often found in plain (also not represented) and 2-2 twill weaves. Fabrics made from plain weaves of cotton are not as breathable or heat-transmitting as cotton fabrics using a single jersey weave.  In fact, a single jersey weave of cotton is a knitted fabric (not a woven one) and has huge holes in it.  So really using these charts to compare the breathability of tight plain-woven lower thread count cotton blankets on the market today is inaccurate.

Terry 3-pile is a thicker weave that overlaps more and creates bumpy ridges you can usually feel in the fabric. Twill is typically signified by a diagonal superficial pattern on the fabric.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

fabric weaves and structures
Look how smooth the 2/2 weave looks. (Mallikarjunan, 2011)

Inside the medical textile study, which fabrics should we be examining to compare?

Using the former insights, we now know we should really be comparing Fabric C (100% Lyocell with 2/2 twill weave), Fabric D (100% micro-polyester with 2/2 twill weave), and Fabric E (100% Cotton, single jersey).

For our viscose comparisons, we will be referencing a study that solely focused on comparing bamboo viscose with bamboo lyocell called “Thermoregulatory characteristics of bamboo / lyocell union fabrics.” 

A necessitated reporting bias towards cotton

Our current analytical approach will put positive bias towards cotton, as we compare bamboo lyocell with a cotton ‘knit’ variant that regulates temperature better than most of the weaves used in cotton fabrics found in weighted blankets today. However, doing so will help us maintain reporting conservatism.  Realistically, the Terry weave more closely represents a plain weave in terms of breathability. (if you look at the picture above, it goes up and down every other one more frequently than 2-2, which goes up and down every other two dots (which stand for threads perpendicular).

Right now is a good time to mention that the high heat conduction values of cotton and bamboo reported below match the findings of another independent study that focused more on how the thermal regulatory aspects of bamboo and cotton compare other natural materials in Part I of Duvet Cover considerations, titled “Why bamboo lyocell?”

SKEPTICS NOTE: If you are a skeptic like me, you will notice that some of the raw material labels for ‘bamboo lyocell’ differ across studies. Adding to the confusion of new consumers researching fabrics that they may purchase, material definitions for “bamboo”, “lyocell”, and “viscose” are regularly mixed up and defined differently across studies. Viscose is often defined directly as ‘bamboo’ especially in China research studies… lyocell also but much less often. (we have only seen lyocell referred to as ‘bamboo’ in material science once out of the 30+ articles we’ve read in total, whereas viscose is called ‘bamboo’ more than 70% of the time) There is a new “Chinese bamboo” that is also called ‘bamboo.’ To find out what materials are really being compared in the studies you find, you can usually find material references in the ‘introduction’ section of other ‘secondary’ studies referencing the study of interest. Useful information about how the fabric samples were derived may also be placed directly in the ‘methods’ section of the article you are reading. The former process requires that you understand the literature surrounding the article, lending insight to its context (the raw material actually being referred to). This can be fairly time consuming (trust us, we know). Another alternative option is you can contact the original primary author for official requested access like we did

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Final battle results…what do the referees report?

Lyocell feels cooler to touch than cotton and micro polyester

Researching on, we find out that bamboo lyocell has greater heat conduction (heat sucking from your hand) rates when compared to cotton.

fabric thermal conductivity
Look, lyocell seems to conduct heat pretty well…(Mallikarjunan, 2011)

When compared to modern synthetic fabrics, bamboo lyocell has higher thermal conductivity than all forms of micro-polyester by a healthy margin of 19%. This includes common weighted blanket materials like micro-fleece, micro plush, microfiber, and minky, which are all modern engineered polyesters.

Not all polyesters are created equal. The ‘micro’ designation is important and represents a modernly invented polyester that has increased durability over most natural fabrics, yet is a lot more breathable and heat conducting than non-‘micro’ polyesters. Micro-polyesters have improved ‘old’ polyesters to share many thermal regulatory attributes with cotton, except for sweat management, as we will see later.

If the product label just says polyester, look to the bar columns above for variables F and G (pure polyester blends with cotton) to get an idea of the heat dissipation of those blankets. Well, its half cotton, and cotton has pretty high heat conduction. So divide bars F and G roughly in half to get a ‘conservative’ estimate. Weighted blankets made of pure polyester or polypropylene are the warmest of us all.

But wait, bamboo viscose will feel coldest to touch

Both lyocell and cotton seem super ‘cool’ when compared to polyesters, but wait, not so fast. According to another independent study titled “Thermoregulatory characteristics of bamboo / lyocell union fabrics” that examined the thermal regulatory outcomes of using lyocell versus viscose blends, bamboo viscose can conduct heat roughly 3x better than lyocell at the weave (2/2 twill) the prior mentioned medical textile study also evaluated.  What this means is that bamboo viscose will feel colder to touch than lyocell.

bamboo and lyocell fabric properties
Look at that, that factor is just under 250% increase in heat conductance going from lyocell’s 0.024 to viscose’s heat sucking property of 0.083.(Kandhavadivu, 2014)

Bamboo lyocell is newer than viscose. The engineers of bamboo lyocell were trying to make bamboo viscose more durable, eco-friendly, thermal regulating, soft, and sweat friendly (spoiler, its all of the above). Bamboo Lyocell and Tencel are popularly used in luxury fashion clothing brands in Europe, a place where increased warmth while increasing air permeability and sweat management is desirable.

In order to exaggerate the comfort characteristics of Lyocell, material scientists had to modify the micro fibrils of the individual fibers to pop out upon contact with moisture and abrasion. This dynamic lowers the thermal conductivity of lyocell versus viscose making it a warmer blanket. However, these fibrils also contribute to Lyocell’s softer purposeful piling tactile appeal (soft and snuggly) and increased durability (increased tear strength, wet or dry). The purposeful change of how Lyocell fabric is finished (decreasing thermal conductivity but increasing durability and surface finishing properties) contributes to the famous Lyocell “cool-warm” feeling that scientists have notated.

It is important to mention here that Lyocell is warmer because of unmentioned mechanical properties of the fabric. (look at the table above: density, thickness, etc) This is due to the intrinsic factors of Lyocell fibers compared to viscose fibers, which creates a more densely packed thinner fabric (smoothness, yeah!) with hundreds of little pores through out. Higher material densities usually result in higher conductivities, just think of aluminum versus glass. However, in the case of bamboo lyocell vs viscose, this natural trend was overcome, silky warmth was achieved… while maximizing breathability and sweat management capabilities. Lyocell’s high natural density may be perfect for preventing sensation of weighted filler beads.

A quote from a scientific article showing how Tencel is cooler than cotton.
(Frydrych, 2002)

Tencel is a branded wood lyocell that uses eucalyptus wood for their cellulose raw material instead of bamboo. Although the raw material properties differ slightly, both are commonly accredited in textile research for being “warm-cool” textiles because their resulting lyocell fibers fibrillate well regardless of raw material origin. Scientists have stated that the material properties that result in Lyocell’s comfort outcomes between wood cellulose and bamboo cellulose raw materials are similar. According to the study, bamboo lyocell is even better, as bamboo lyocell has greater anti-bacterial and negative ion properties than wood lyocell. These properties are more important for a material that is designed to be right next to your skin. Thankfully, truHugs 1 uses bamboo lyocell as its cover material, not wood lyocell.  If you look deep into the study by Frydrych, you can compare its results with the medical textile study to really gain insight on the thermal regulatory comfort differences between bamboo lyocell and Tencel fabrics by using cotton as a relative measurement base.

Lyocell is more breathable than viscose and most other fabrics

physical and thermal properties
Here, its already 95% more, but on plain weave its more like +30%. (Kandhavadivu, 2014)
water vapour permeability
Note how the air permeability differences between viscose (stated as bamboo in this study) and lyocell are less than before. (Kandhavadivu, 2014)

With 1/3 twill weave (which is 1 horizontal perpendicular weft thread per every 3 vertical warp threads on a loom), the air permeability differences between viscose and Lyocell are less because the material properties of the weave allow more air to go through both fabric types. Imagine only tying down 3 wooden logs with 1 string wrapping all 3 as a whole unit, those logs might roll more if touched. Now imagine lacing each log up and down in an alternating fashion. That particular configuration is not going to be as air permeable due to mechanical structure. There is simply more string per log. This is a great example of HOW extreme the thermal regulatory effects created by the weave of your fabrics can be.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Going back to the medical textile study, we find that bamboo lyocell (especially the weave most likely to be used in blankets a 2/2 twill) is up to 212% more breathable than cotton woven with terry 3-pile, the weave closest to the plain weaves used in other weighted blanket cover fabrics today. (whether serving as a surface fabric for an inner or an actual cover)

Also, 2/2 twill bamboo lyocell breathes better than micro-polyester fabrics with the same weave, up to +20% more than minky, plush, microfibers, and all other forms.

Another good example of the inverse relationship between heat dissipation (thermal conductivity) and air permeability exists in this study. The low air permeability of the terry 3 pile lyocell and cotton make sense, as these are thicker weaves with more overlap. Now compare Figure 3 below with Figure 4 posted above. Notice how the thermal conductivity is higher for terry Lyocell when compared to 2-2 twill Lyocell, yet the air permeability is lower for terry Lyocell. Theres that inverse air permeability/sweat management and heat dissipation fabric relationship again! As you review the literature, you will notice that Lyocell performs consistently better than cotton independent of weave when it comes to thermal regulatory comfort with exception to thermal absorption. With similar weaves, it’s simply a better fabric.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

air permeability in fabric
I hope you don’t buy weighted blanket G, which represents a cotton / polyester blend. Haha. (Mallikarjunan, 2011)

Lyocell and cotton beat micro polyesters and match engineered acrylics at sweat absorption

Lyocell and cotton will absorb and dissipate your sweat vapor better than micro-polyesters. Cotton/poly blended fabrics engineered for sweat absorption like CoolMax (acrylic, but similar in many comfort aspects) can keep up

water vapour permeability
(Mallikarjunan, 2011)

Lyocell will also transport a lot more of your sweat vapor better than traditional ‘bamboo’ viscose. According to Table 3 posted again below (again, 2/2 twill values to control for confounding variables between studies, also the most common variant of bamboo lyocell other than plain in bedding textiles), you see that Lyocell water vapour permeability is 165% more than viscose. Basically, if there is any time of year when you sleep and there is risk of sleeping hot because of the surrounding hot weather or high humidity, Lyocell may be a better choice than viscose.

thermal properties of bamboo and lyocell
(4967.3-1874.07)/1874.07 = 1.65 = 165% (Kandhavadivu, 2014)

Our opinion on what these results mean

The good news about high thermal conductivity materials inside weighted blankets is that they feel cool when you touch them with your hand.  This makes them awesome conversational pieces when you are trying to impress an attractive date….but horrible for sleeping comfort.   Bamboo viscose’s low thermal flexibility might make weighted blankets wrapped with this fabric too hot to bear for some.

Lyocell…

  • Provides better temperature regulation than viscose because of its breathability, actually viscose’s breathability is worse than micro-polyester’s!
  • Doesn’t feel as cold to touch initially as much as viscose.
  • Feels cooler during daily movement due to texture finishing properties (nano-engineered to be so…this article talks about how the cool silky feel of Lyocell is a byproduct of Lyocell’s surface properties and finish).
  • Absorbs sweat if the environment is too hot better than viscose.

Ultimately, breathability of a fabric is the most important aspect of thermal regulation.  This is because its the air between blankets and our body that keep us warm, or cause us to wake up to sweat, not the blanket itself.  Its kinda like how on those adventure shows into cold places they dig a little snow cave and sleep in it, the air inside their newly dug pit prevents them from freezing to death.  Thus, even though viscose initially feels colder to touch than lyocell fabric, its low breathability may cause night sweats.

Sneaky peaky, another study titled “Investigation of Regenerated Bamboo Fibre and Yarn Characteristics” shows a table about how Lyocell is much more durable than viscose.

various physical parameters of the fibres
Note here, that the dry and wet tenacities are nearly 2x for lyocell when compared to viscose. Please read the original article to really understand how lyocell is more durable than viscose. Lyocell does have a weakness, it can be destroyed by hot ironing. The lower moisture absorption here pertains to lyocell fibers, which is at a more granular level than lyocell fabrics. Lyocell fabrics, after they are woven from Lyocell yarns, which are formed from multiple Lyocell fibers… have better moisture absorption than both cotton and viscose. (Erdumlu, 2008)

The high likelihood of data misinterpretation for the table shown above shows how one must take care when researching thermal regulation aspects of fabric materials by clearly designating whether it is the “fiber” or the “fabric” being researched. In the case that insufficient research is presented for the fabric…at least to the point for objective material comparisons, one has to dive as deep as the molecular properties (even more granular than the fiber microscopic level) to derive useful theoretical conclusions. Now it’s time to ask if a $200 weighted blanket purchase warrants that much cost in research time. For most of us, the answer to that rhetorical question is a clear resounding ‘no.’ It’s not like you are buying a house, LOL. Don’t worry. It’s ok. We will summarize it all here in tables and graphs for the months to come so you can read it in 5 minutes.

Lyocell is kinda like a human cell  That is no surprise because Lyocell is really taking a natural cell’s framework and nano-engineering its water absorbing properties and breathability to be on Marvel super hero performance levels. Starting a physics problem from step 7 (prior steps completed) is much easier than starting from step 1. (which is metaphorically the case for the progression of synthetic fiber research)

With the results from merely two studies (which is definitely a limitation, many studies report similar outcomes), viscose becomes the king of heat conduction whereas lyocell is the king of air transfer and sweat management among premium bamboo fabrics that simply outclass cotton and micro-polyesters in function and form.

I don’t want to sound like a sales person but these are the facts as to why we chose Lyocell for our cover fabric. Cotton has other advantages over bamboo that help with providing a breathable heat reserve that is adaptable to all sorts of environmental conditions, but its aforementioned disadvantages definitely designate cotton as an inferior blanket fabric layer that would be designed to be in contact with your skin (another spoiler of what will be discussed later…particularly the rough surface texture and the innate unevenness of cotton sheets causes problems for people with sensory disorders).

With the results above, you now know Lyocell is feels warmer to touch than viscose, but reduces likelihood of waking up to night sweats more than viscose because of its breathability. Its definitely more breathable than plain woven cotton and all forms of polyester. You also know micro-polyester is cooler than cotton/poly blends (aka. fleece), but warmer and less sweat absorbent/breathable than pure natural fabrics. In terms of breathability and not waking up to night sweats we have lyocell > micro polyester > viscose > cotton > cotton & polyester blends > pure old world polyester. Next, when we talk about unique considerations that may address different people’s needs, please pick the best weighted blanket for yourself.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Our opinion on what makes the best-weighted blanket depending on who you are

Bamboo lyocell is the best cover material if you want to ensure comfortable continuous sleep without waking up to night sweats regardless of seasons

Bamboo lyocell supernatural breathability will prevent you from waking up from night sweats all season round.   As air between the blanket and your body is the primary insulator that cause you to overheat, the maximum air circulation afforded by bamboo lyocell will serve you well in nearly any climate.

If you sleep with your air conditioner on and your feet exposed, viscose might be a good option

Even though viscose has low breathability, eventually allowing hot air to accumulate and overheating to occur…it does feel cold to touch, initially.  Thermal conductivity of fabrics is almost a negligible factor when talking about thermal regulation because the heat sucked up by fibers is so low when compared to the heat carried through the air by breathability.   Don’t believe me?  Compare the air permeability and thermal conductivity values in the charts above and convert the units.  To really solve this problem, you simply have to research the unknown given of how fast a specific amount of air can absorb heat and the solution can be derived in less than a few steps.

However, if you sleep with open access to your environment (feet sticking out, big gaps around the edges of the blanket allowing air to come in) and use an air conditioner, breathability no longer becomes an issue and you might actually appreciate the ice cool touch of viscose.  Also, viscose has higher water absorption ability than most weighted blanket fabrics on the market, including lyocell.  (unreported above because this parameter is unrelated to thermal regulation but found in the original cited study) Here, water absorption does not refer to sweat transmission capability, rather…this refers to how fast a fabric can absorb liquid in a cup and dry.  This strength may make bamboo viscose more suitable in weighted blankets that need to be spill-resistant…like when used by children and disabled adults who wet the bed.

Don’t like doing laundry? Break your iPhone all the time? Cotton (warmer finishes) and micro-polyesters may be a good option for those living in colder climates who value convenience and durability

For our friends who live in colder regions like the states of Maine or Washington, we want blankets that have fabric covers with low “thermal conductivity” and high “thermal resistance” to warm you up more quickly and keep the heat in the air between your body and the blanket. Commonly used weighted blanket materials that fall into this category are 200 TC cotton, polyester, micro-polyester, and cotton / polyester blends.

200 TC Cotton as a cover alternative

If the innate roughness of cotton doesn’t turn you away, the positive aspects of cotton designate the fabric as the perfect natural alternative for people in cold climates. In these cases, between cottons yarn construction (tex and ply), weave and thread count all matter. Low thread count cotton is commonly mis-advertised as high thread count cotton when each yarn within a thread is counted as a thread itself which is why the single ply designation is so important as this fabric feature completely changes the fabric’s comfort outcomes.

Cotton covers commonly made for weighted blankets are woven sateen (flexible to the thermal regulatory requirements of more people) or plain (synonymous with percale, warms up quicker, risk of overheating due to low breathability over longer durations under the weighted blanket).

Some of the low thread count cotton fabrics that wrap the actual weighted blankets (non-detachable cover fabrics) in our space have their breathable gaps sealed by a glue film solvent in order to help counter batting and weighted bead leakage with the primary goal of reducing overall material costs. (233 TC, wholesale) . The second option is the fabric is used with a scrim.  (200 TC, wholesale) Using either a scrim or ‘sealed’ lower thread count cotton fabric applied during the fabric finishing stage completely makes the surface fabric of a weighted blanket unbreathable (more prone to cause you to overheat over time) while increasing overall blanket durability. (hey thats good!)

Out of these 2 thermal regulatory comfort evils, weighted blankets with scrims (200 TC) are BETTER than weighted blankets with fabrics that have a film finish (233 TC)…however sometimes in the market BOTH of these design elements are present in the same product. Sometimes, fabrics that have had undesirable films applied can be differentiated because the cotton fabric will have an unnatural dull sheen and appear more rigid in product photos when bent. If you unfortunately already bought one of these, you can tell because when you try to blow through it, no air comes out on the other side. (zero, literally)

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

Conclusively, most weighted blankets wrapped with low quality cotton warm up quicker upon use but also have decreased probability of meeting each of our thermal regulatory requirement differences due to our unique personal characteristics and evolving environmental contexts.   For some, weighted blankets surrounded by low quality 200 TC cotton might be ‘OK’ in the winter, but then too hot for summer.  For sleepers who release a lot of body heat, these weighted blankets are probably not as appropriate.  You probably release a lot of body heat if you are skinny or more athletic.  If you are a cold sleeper, you might give weighted blankets wrapped with low quality low thread count cotton a shot because of how cozy they are due to the way their fabrics are prepared.

Micro-polyesters (fleece blends, minky, plush, micro-fibers) as a cover alternative

With regards to synthetics, new micro polyesters like micro fleece, micro fiber, and micro plush sheets have similar or lower thermal conductivities and air permeabilities when compared to cotton. Stated differently, new advances in micro-polyester material research have made these plastic fabrics nearly as breathable and heat transmitting as cotton.  However, in general…they still have the deficit of having less sweat vapor permeability.

Micropolyester fabrics tend to be warmer than natural fabrics because their chemical composition causes their fibers to roll up in little balls, creating many little intra-fabric air spaces that can trap air.   Thus, micro polyesters are warmer than natural fabrics because over time synthetics use trapped hot air itself as a natural insulation material…making these fabrics ‘feel’ warmer after heat flow stabilization than natural fabrics.  Final sleeping temperature after heat flow stabilization is a different independent variable than thermal flexibility.  We will talk more about this complex topic in-depth later.

Perhaps the most positive attribute that can be stated about micro-polyesters that gives them an edge over natural fabrics is that they DO NOT SHRINK. (this is such a big plus I had to put it in all caps) In addition, you can have a bunch of cool embossed patterns on plastic blankets like “Gravity Grid” and old fashioned “space bump” designs, trendy kick-back visual elements that might add to the sexy interior decor of your extremely modern bedroom.

Comparing thermal regulatory outcomes between the two more affordable fabric options in the weighted blanket market:  minky and low thread count cotton.

In our specific space, weighted blankets wrapped with minky fabrics (without a supporting polyester scrim) are in high likelihood more breathable than weighted blankets wrapped with low quality cotton that has had an air impermeable film applied during finishing.  (200 TC) . This makes real minky more flexible (when compared to formerly described LQ cotton) to the dynamically changing thermal regulatory requirements of the population as a whole.

With any weighted blanket, make sure to analyze all layers.  Many weighted blankets with a breathable cover might have an unbreathable fabric wrapping the weighted blanket itself.  Once again, this trend is motivated by the economical need of having an attractive value proposition…enough to generate sufficient demand…while cutting quality on points rarely mentioned to consumers to reduce operational overhead.

Dual material covers: blending synthetic with natural

From your new learnings in textile science you should now understand that a dual-sided hybrid cover constructed from two materials does not make a cover more suitable for all seasons.  Instead an inferior inexpensive synthetic thermally ‘inflexible’ fabric, minky, is substituted in place of a more expensive thermally flexible natural fabric.  In order to escape, heat has to go through all layers of your weighted blanket, so the minky limits the maximum thermal flexibility of the weighted blanket as a whole.  Further, most bamboo advertised is really “bamboo viscose” making weighted blankets covered by these fabrics extremely unbreathable and terrible at thermal regulation.  If you already bought one of these you can postpone overheating by putting the more breathable side against your skin using the new knowledge you gained here.

Engineered cotton-polyester blends as a cover alternative

It seems like cotton and plastic fiber blends are simply inferior fabrics across the board for all comfort aspects with regards to blanket thermal regulation. As an exception, certain cotton polyester blends and modified acrylics (like CoolMAX) are specifically engineered to have high sweat vapor permeability, like Fabric F.

Fabrics like CoolMAX and Thermolite are engineered acrylics which tend to have high sweat absorption and fast drying times. If you have more interest in directly comparing CoolMAX directly to cotton and bamboo viscose, please visit “An Investigation of Knitted Fabric Performances Obtained From Different Natural and Regenerated Fibres.” Acrylics are another set of synthetic fibers that are less durable than polyester, but more comfortable because of their high sweat absorption abilities.

Sweat absorbing synthetics are really designed to provide high warmth during and after vigorous physical activity, not for sleep, as they have the combination of high thermal insulation and low air permeability. The total amount of sweat they can absorb and how fast they can dry is extreme, with maximum range values way beyond those typically needed during sleep. Honestly, you would only sweat this much running on a tread mill. This makes engineered acrylic fabrics more suitable materials for tank tops or running shorts during cold early morning neighborhood runs, where the entire body isn’t covered by the fabric like it is when using a weighted blanket. In other words, when CoolMAX is used with “open air” clothing, the low breathability factor of CoolMAX does not really impact your comfort like it would when wrapping your whole entire body.

Be wary of cotton / polypropylene and cotton polyester blends, they may be the warmest but also lack the improved breathability of micro-polyester (up to 400% higher air permeability than outdated plastic sheets…which is tons). If you are going to go with synthetic fabrics for a workout or because you live in a humid swamp outhouse, look for blends that are designed to have higher water vapor permeability for sweat vapor management like CoolMAX.

The negatives of natural fabrics, they tend to shrink

Cotton shrinks up to 20%. Luckily, most weighted blankets have high-loft polyester fillings to resist cotton shrinkage. Careful about cotton weighted blankets that lack battings with sufficient loft to resist shrinkage. Bamboo lyocell shrinks on average an estimated minor 2-3%, 1% less than bamboo viscose’s 3 – 6%. Covers should be sized to account for shrinkage

The high elongation values of bamboo viscose and “China Bamboo” fibers (look at durability table above, this conclusion is drawn in the study that table came from) makes them more prone to shrinkage.

– truHugs Quick Tips: Comparing weighted blankets on the market yourself.

A note on weighted blanket material softness

Simple jersey woven cotton has the same thermal conductivity and breathability as lyocell, but can serve as a warmer material in the instance that its blended with a bit of polyester or woven as a warmer variant. Unfortunately, cotton feels rougher to touch when compared to bamboo lyocell because of its fiber properties. Supporting this conclusion is USTER’s recent comparison on the tactile feeling between viscose and cotton.

Another independently conducted dermatological study titled “Dermatological examinations on the skin compatibility of textiles made from Tencel fibres”, found that 90% of the patients with atopic dermatitis or psoriasis preferred Tencel (wood Lyocell, but still pretty similar in its material properties to bamboo Lyocell) “to their own clothing and bed textiles regarding skin compatibility.” They continue describing, “The patients gave excellent scores for TENCEL textiles regarding improvement of itching, skin sensitivity, thermoregulatory properties, for its properties of cool, smooth, and dry feelings, and for its compatibility with the local topical treatment.”

Science VS Metaphysical principles that rule the universe

Different strokes for different folks

Philosophically, we all have different beliefs and values. Our actions reflect our beliefs and values. Ok, enough of a philosophical tangent that is somewhat biased, as these conclusions are heavily influenced by the constraining frameworks of human development theory.

A young college male who lives in a fraternity house probably wants a micro-polyester weighted blanket to help him relax after his raging all-nighter party. He can walk it over to LAUNDRY-O-MAT and wash it “no prob.” He can stay warm as he’s coming down the next morning from his “Fear and Loathing in Las Vegas” road trip. Without intention to bias perception with this seemingly negative scenario, many of us (including myself to some extent) really live the non-stop lifestyle depicted above. Most of us are really just too busy to be worrying about dusting, laundering, and “spring cleaning” all the time. Much less fixing that half-broken dishwasher thats been working ‘alright’ for a year. Life balance always seems so hard to achieve with the randomness of life.

Another girl is a professional who lives in South Carolina. She needs a blanket that is warm for cold winter nights because she lives near Folly Beach. She also values air breathability and moisture management for those ‘humidity’ waves that come in after a rain storm. She has already tried pure micro-polyester, old polyester, and/or cotton/polyester blends during these times and found them to be constrictive, too hot, and sweaty. Function becomes more important than convenience. Natural fabrics can provide some relief in this situation.

Modern micro-polyesters = convenience + durability + faster warm up times + overall warmth + shrinkage resistance – sweat management – air circulation – heat dissipation rates

As you can see, they have managed to engineer plastic sheets to be either better at sweat management (cotton / poly blends) or breathability/thermal conductivity (micro-polyester). The data above shows there is a functional trade off with synthetics, you have to pick synthetics based off their extreme strengths which were probably the engineering goals of that particular material.

Material F as a polyester / cotton blended fabric has characteristics roughly match that of acrylics…like CoolMAX. According to a study titled “An Investigation of Knitted Fabric Performances Obtained From Different Natural and Regenerated Fibers”, CoolMAX is very warm (they were designed to trap air in their fabric airspaces for warmth), lacks breathability, but excels at sweat absorption. Buy CoolMax fabrics for daily use when they are to be used in tank tops or shorts, where lack of breathability through the fabric isn’t really a concern. Fabrics like these shouldn’t be used in the case where the fabric covers your whole entire body, because breathability and comfort are then more closely tied.

Supporting this conclusion, another scientific study confirms that synthetics like CoolMAX or modern polyesters are predominantly designed for high levels of activity, whereas natural fabrics are better for comfort during low-intensity activities, like when you are sleeping.

As a minor notable trend unveiled by our literature review, micro-polyesters emulate thermal regulation aspects of knitted cotton, with lower sweat vapor permeability. For some, this may make micro-polyesters worth a try because the added value of durability, convenience, and heightened superficial appeal outweigh polyester’s lower sweat management capabilities. These aspects can be more important if the weighted blanket is to be used in more public areas, where your prized possession will gain more visibility and resist accidental spills as you are watching Monday Night Football with your friends. Accidental spills on micro-polyesters aren’t even absorbed in large part, liquids will just ‘bead’ on the surface of the fabric, just like your sweat might. This definitely makes plastic sheets easier to maintain, as you can just wipe that juice spill right off during multi-person day use as a throw.

Confusingly, with the way low thread count cotton is typically prepared (woven plain, finished with air impermeable film) in the most affordable weighted blankets as of late 2019, micro-polyester may be a better option when prioritizing thermal regulatory comfort flexibility.  When selecting between budget friendly micro polyesters…. price jumps of around $30 – 50 designate a more thermally ‘forgiving’ fabric is most likely being used.

Cotton + Bamboo = higher air circulation + better sweat management + faster rates of heat dissipation – shrinkage issue – convenience – durability

Natural fabrics win in thermal regulation aspects for sleeping comfort but lose out in convenience, and durability. (assuming they aren’t gooped up with air impermeable fabric finishes or supported by polyester scrims) The biggest downer to micro-polyesters is that they lack ability to transport sweat.  Plastics aren’t naturally hydrophilic (water-loving). In fact, these fabrics often resist water absorption with the ways they are finished. Combined with their high warmth, this lack of sweat absorption may cause issues for many.

Natural fabrics are more of a hassle to maintain. For example, bamboo lyocell fabric, because it’s made from cellulose building blocks, scorches if an iron is too hot during maintenance.

In the end, if you don’t mind 20 minutes extra work every few weeks, and you need a super comfy personal blanket you will sleep with every night… instead of use as a public living room throw… natural fabrics definitely win out in providing you with sleeping comfort as more breathable, sweat-absorbing, and heat transmitting fabrics.

As animals, we are part of nature. It is no surprise modified (chemical or mechanical) natural plant fibers are better for human skin than modified petroleum. In this way, human technologies accentuating plant fiber characteristics, which are naturally conducive to the transport of water and air for plant survival, create a more comfortable sleeping experience than materials engineered from oil. Many polyesters do have the positive benefit of recycling petroleum to avoid environmental waste dumping.

Social gossip about polyester fabrics that are probably not true

There are questionable public concerns circulating around polyester’s “static electricity” properties. The whole hypothesis revolves around how polyester attracts negative ions to it like crazy, leaving you positively charged. This has to do with the wellness concept of grounding and human body electrical balance. Even though there are several studies on this, I don’t think I will state their preliminary findings as ‘fact’ here. It could be a bunch of hocus pocus sold to the public by merchants of natural sheets to increase sales demand. The false unproven concerns around the electrical nature of polyester contributes to the excessive “BS” clutter on my research windshield from biased marketing information while searching for the truth I can barely see to keep driving ahead. However, I thought I would present the general concept for thoroughness.

In addition, specific people have allergies to plastic sheets. This is only a very minor portion of the population and shouldn’t deter you from the offered convenience of micro-polyesters if that’s what you value.

If you find out you are allergic and develop rashes, then you have no option but to choose natural fabrics with the increased required inconvenience associated with their maintenance. Most online retailers offer a risk-free return policy, so why not try different stuff out!

Related reading

TruHugs 2 Release Updates – Here, we briefly cover what makes us different than most weighted blanket companies while accentuating how differences in weave and fiber fineness affect your thermal regulatory comfort.

Jonathan THWB
Jon THWB

When my brother started truHugs, I was skeptical as to whether weighted blankets really worked. Using my research background in Kinesiology I quickly dove into the science to discover that weighted blankets, to my surprise, have some documented positive effects during use. Obsessed with product improvement, I promise to use my background in a diverse field of sciences to continually help improve our products for maximum comfort and benefit. I hold a M.S. in Kinesiology and M.B.A. along with 13 industry related certifications.

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