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Keep Hot Hot and Cold Cold with Thermal Fabrics

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Years ago the Thermos® company had the slogan, "Keeps hot things hot and cold things cold." You can't say it much better than that. Did you know there are fabrics that help you do the same thing? These aren't the heavy industrial materials that keep steelworkers, astronauts, and firefighters safe, but honest-to-goodness fabrics you can actually sew with. 

Thermal fabrics are useful for all kinds of projects where you want to keep hot stuff hot and cold stuff cold, such as pot holders and oven mitts, table pads, lunch carriers, shopping totes, ironing board pads, outdoor stadium cushions, tea cozies, and many other items.

And, because of the metallic coatings common to many of types, and the fact that they're easy to sew, you can even use them to make some pretty creative costumes – from medieval armor to Lady Gaga!

The options fall into three basic categories: 

  • Thermal Batting, which has insulating properties.
  • Thermal Fabric, which can withstand high temperatures without scorching.
  • Thermal Interfacing, which is a lighter weight insulating option.

An important note about microwaving: The materials listed below that have a metallic layer specifically say, "Do not microwave." None of the rest actually state they are safe to microwave either. So for any kind of thermal fabric, unless it specifically says it's microwavable, we recommend you don't risk it. One exception, described at the end of this page, is Wrap-N-Zap by Pellon, which is specifically designed to be microwaved.

Thermal Batting

Insul-Bright

The thermal batting product that's been around the longest is Insul-Bright from The Warm Company. It's made with hollow, polyester fibers that have been needle-punched through a nonwoven substrate, and then through a reflective metalized poly film. The needled material is breathable. The hollow fibers insulate by resisting conduction. And the metalized poly film resists radiant energy by reflecting it back to its source.

It contains no resins or glues and will not shift, migrate, or bend. You could use it in clothing, but it would be rather noisy. However, babies and animals often love the noise and like to scrunch it up in soft books and toys.

Insul-Bright is machine washable, easy to cut to size, and apart from being just a bit slippery, is quite nice to work with. Most sources offer it by the yard in 22" and 45" widths, and a few outlets offer 36" x 45" pre-cuts. 

Even though we've listed this material in the 'batting' category, The Warm Company does suggest considering two layers or layering Insul-Bright with a standard cotton batting if you are using it for a high-heat application.

A number of sources offer Insul-Bright online, including Fabric Depot, Jo-Ann and Fabric.com. It's also readily available at many local fabric and craft stores.

Insul-Shine

This space-age thermal batting from The Warm Company was originally designed for insulating air conditioning ducts or wrapping your hot water heater (for which it's very effective). But Insul-Shine is actually quite sewable.

You can make something simple, like a reflective visor for your car or to put in your RV windows to prevent sun damage. If you're looking for a mod metallic look, you could also use it to cover a headboard, throw pillows, or make a budding astronaut very happy with some rocket wall art.

Insul-Shine has two layers, reflective material and insulating polyester batting. The metal surface wipes clean and actually acts as a water barrier for soft coolers, diaper bags, and bottle carriers.

It is washable, but doing this may dull the reflective side. Sold in 22" and 45" widths.

You can find it at Amazon and Fabric.com among others.

Insul-FAB

Also made by The Warm Company, this thermal batting is very similar to Insul-Shine, but Insul-FAB has an additional layer of white lining-style fabric. It's a good solution when you want a smoother and more comfortable finish on the interior of your project. 

Because it's designed not to show the insulation, it's perfect for insulating totes, lunch sacks, casserole covers, and more.

It's also machine washable and dryer-safe. We found Insul-FAB by the yard in a 22" width at CreateForLess.com and in a 45" width at Fabric Depot.

Solarize

Solarize, a new thermal product by Fairfield, is a uniquely thin metallic insulating fabric. Less noisy and crinkly than other offerings, Solarize still creates a strong thermal barrier that keeps things hot or cold. And it works with the shiny side in or out – you choose. Keep the shiny side exposed to help conduct heat or reflect light. 

It is a sew-in product, made of 50% polyester + 50% aluminum, and the standard width is 22”. You can purchase it as yardage or get it in a “grab-and-go” pre-cut package of 22” x ¾ yd.

Use Solarize inside pillows, fabric scarves, mittens, jackets, hats, and blankets for added warmth. Add it to casserole carriers, potholders, and trivets.  Cool things down by Solarizing inside can cozies, thermal freezer bags, or ice pack wraps. 

You can purchase Solarize directly from Fairfield or find it Walmart and other retailers. You can also buy full bolts from Amazon.

Thermal Fabric

Iron Quick

Iron Quick is a specialty fabric made of 100% aluminum with 100% cotton backing. It's designed to protect from heat (up to 399˚), but does not have any insulating properties so it's long been the go-to choice for things like ironing board covers. 

When you need insulating as well as heat protection, like in your oven mitts, Iron Quick also comes as a quilted material. This is simply the regular Iron Quick fabric with a 100% cotton backing, plus polyester batting and a polyester/cotton backing. This doesn't afford a huge amount of insulation, but you could use more than one layer or add a layer of regular or thermal batting. 

Both varieties come in the same 45" width. When sewing, you should use a size 80/12 needle. 

Neither Iron Quick products should ever be used in the microwave.

Both can be machine washed but should then be air dried – not tossed in the dryer. You can also use a damp cloth to wipe clean.

Nancy's Notions carries both types of Iron Quick products by the yard.

Therma Flec

Therma Flec is a lightweight, heat resistant cloth similar to the Iron Quick but made from 80% cotton/20% polyester. It is scorch-proof to 360˚, but like the Iron Quick cloth, does not provide insulation. However, also like the Iron Quick, you can find Therma Flec in a quilted version for items such as hot pads, oven mitts or ironing board pads. 

Both the flat cloth and the quilted option are available in two colors: silver and light gold, all in a 43-44" width. Don't put this product in the microwave.

We found Therma Flec, in both colors, several places online, including Fabric.com and OnlineFabricStore.

Thermal Interfacing

Thinsulate

Back in the 1980s, the 3M Company introduced an amazing new insulating material called Thinsulate. Ounce for ounce it had one and a half times the warmth of down and twice the warmth of other high-loft insulation materials. It meant you could get sleek ski gloves that were just as warm as giant, puffy mittens.

A quarter century later, Thinsulate is still amazing. Made from microfibers that are only a tenth the size of of other synthetic insulation, it's much more effective at reflecting back heat. And Thinsulate absorbs less than 1% of its weight in water, allowing it to retain its insulating ability even in damp conditions. You can use it in any kind of project where you want to keep warm but don't want a lot of bulk, such as jackets and blankets.

You can get varying densities of Thinsulate, depending on the weight and R-value (insulating property) you want, from 1.6 up to 2.9.

Thinsulate is machine washable and dry cleanable once you have sewn it inside your project. It is a bit tough to find as yardage, but we did locate Thinsulate online at Vogue Fabric Store and The Rain Shed. It's available by the yard, 60" wide.

Thermolam

 

Pellon makes a 100% polyester interfacing called Thermolam, which is a needle-punched fleece with a protective scrim that can provide some warmth. It's available by the yard at a 45" width as both a sew-in or a fusible and is machine washable. It's considered a heavy-weight in the general world of interfacing, however, it doesn't have any loft, so it isn't a choice for projects that call for high-level insulating and/or padded properties.

There's no microwave warning for this fabric, but then again, we couldn't find anything that said it was okay to use either. Maybe you should just forget the microwave, huh?

Fabric Depot offers a good price on Thermolam by the yard (both sew-in and fusible). 

Wrap-N-Zap

Wrap-N-Zap by Pellon is the only thermal product mentioned on this page that we can safely declare to be microwave safe. It's got Zap in its name and it says "Microwave Friendly!" right on the package.

Made from 100% cotton batting, without glues or other chemicals that could leach into foods, Wrap-N-Zap is designed for projects like insulated baked potato bags and casserole warmers – situations where you heat up the food inside the cover and leave the cover on to keep food warm.

You can machine wash Wrap-N-Zap after you've sewn it into a project, but you should only use cotton fabrics, threads, and trims to insure it retains its full microwave-safe designation. 

We found it in a 45" x 1 yard package at Joann Fabric and Nancy's Notions.

Thermal fabrics are a "hot" trend

When we first researched this topic several years ago, we could only find about four kinds of thermal fabric or batting that was sewable and relatively easy to locate as yardage. Now we're finding a lot more options. And we didn't even include all the new energy-saving materials you can sew into things like super thermal window shades. It's nice to see the selection growing. 

Be adventurous and try some projects that are made to keep hot things hot, and cold things cold. Below are a few Sew4Home projects to get you started:

Casserole Carrier

Insulated Baby Bottle Carrier

Lunch Bag

Picnic Tote

Hot Pads

Oven Mitts

Two-Handed Potholder

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Comments (131)

Leela said:
Leela's picture

I want to make a picnic blanket that blocks heat or cold from the ground. Which product is best?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Leela - there is no one right answer as there are a lot of variable in terms of the size of your blanket, what type of fabrics you're using for the top and bottom, if the slight crinkly noise of many of the metallicized battings would be annoying to you... etc. If it's a big blanket, your most efficient layer might be a commerical space blanket. They are big and inexpensive and you can even layer more than one -- something like this: http://amzn.to/2nW1ImV

Whatever you choose, don't forget that you'll want to sandwich the material between a top and bottom layer, and you may want to consider a water resistant layer for the bottom (like a rip stop nylon). For our outdoor lawn cushions, we weren't too worried about heat/cold and so used a polyester batting between a sturdy twill and a rip stop: 

http://www.sew4home.com/projects/pillows-cushions/water-resistant-lawn-c...

Ray said:
Ray's picture

Hi, great article. My situation is I live in the tropics and have a small refrigerator on my balcony that receives direct sunlight in the morning hours until the sun is high enough that the fridge is in the shade. In the evening the fridge goes down to desired temp but as soon as the sun hits it the temp rises rapidly. So I am looking for the best "blanket" I can place over the fridge on three sides (without covering motor etc.) that will keep the cold in and reflect the sun's heat away from it. I realize I will probably have to place some weight of somekind on top of the blanket to hold in place because of the wind. Thanks

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@ Ray - We're a home décor website, so yours is not a situation we have experience with. That said, one of the denser thermal wraps, like the Insul-Shine might be a good option. You may also want to contact a local home improvement outlet to see what they suggest for insulating -- especially in your specific climate. You might be able to simply put up a shade cloth that would help keep your fridge in the shade in the AM.

Milly said:
Milly's picture

Hello!

I have a project in which I need to have a bodysuit which will protect someone from extreme heat AND extreme cold as well as lightning storms and tsunamis. Is there any typw of fabric which would fit this description?

~Milly

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@ Milly -  not that we've ever heard of - it sounds like something only a super-hero would have.

Crystal Bay said:
Crystal Bay's picture

Hi there! amazing article and research!

I am looking for a very high quality insulation lining to make a high-end lunch bag with. any suggestions on the type of materials besides the common fabrics above? 

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Crystal Bay - Thank you! The options outlined above are the main ones of quality currently on the marketplace. I don't know of any "higher end" products. You could certainly do additional research directly with the manufacturer's to see if there's something you like better. The Warm Company produces the widest variety: https://warmcompany.com/ -- Fairfield World offers solutions as well: https://www.fairfieldworld.com/

Anonymous said:
Anonymous's picture

Hello, this might sound a bit crazy but I was hoping if you knew a short list of insulating fabrics that are 100% natural, as I am making a coat for my rabbit and therefore they need to be animal friendly. Thank you so much.   

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

A coat for a bunny sounds pretty adorable. The thermal fabrics are indeed usually made up of all or at least part synthetics in order to get the insulating or reflective properties. For all natural, your best choice would probably be in the traditional fabric area. Maybe one or more layers of a 100% cotton batting or a soft wool. 

SewingHobby said:
SewingHobby's picture

Hi, 

I am looking for a insulation that I can use to sew mittens/gloves for my toddlers. 

What would be a good fit for Winters with -15C. 

What would you recommend and where can I buy such material.

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@SewingHobby - Based on your description, it sounds like Thinsulate would be your best option, perhaps in combination with the Solarize. There are links above to some where to buy options. 

Diane Beaulieu said:
Diane Beaulieu's picture

I'm making a wood ironing board. I'm using warm and natural, insul bright and a cotton canvas. What goes against the wood? Warm and natural or the insul bright?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Diane - Different folks prefer different layering, and not everyone adds Insul-bright - so there's not one perfect answer, but in general most folks prefer the regular batting under the canvas cover for the smoothest pressing surface.

Diane Beaulieu said:
Diane Beaulieu's picture

Hi Liz

Any suggestion on what to put against the wood to prevent mildew and moisture when using steam from the iron?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@ Diane - You're moving beyond our area of expertise since we never attempted a project like this  but in general, I think you might be better off treating the wood with a sealer or other similar product to repell moisture rather than relying on the fabric.  Other than that, perhaps making sure you let the board dry/air out after a heavy steaming session would be a good idea. That said, I'm really guessing!

Joe P said:
Joe P's picture

Could any of your products be used to insulate a dog house?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Joe P - These are actually out products -- just a review of a few of the most popular options out there for home decor projects. We've never attempted anything like a dog house, so don't have a specific, tested recommendation for you. In general, one of the heavier options, like the the Insul Fab or Insul Shine would likely be the direction to head. Do remember that they aren't water/weather proof. You'd likely want to layer the insulation with another fabric to protect against them getting wet and/or the dog chewing through it. 

Joycedia said:
Joycedia's picture

What would you suggest for the Inside of a dog coat for use by dog sled dogs?  Needs to be durable, warm, soft to move as they run. I need to make 20 of these coats and need some insight for inner and outer layers. TiA!

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@ Joycedia - As a home decor website, that particular project is outside our experience and expertise. You need some very specific features for such a demanding use. A good place to start might be to examine how and with what the commercial coats are made and reverse engineer from there. 

Nancy H said:
Nancy H's picture

Can any of these materials be used to make an insulating blanket for pellet grills?  (Temps up to 500 degrees but interior temps often less than 300 degrees Fareheit.  Thanks!

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Nancy - That is a specialty use that we have not tested for. You would be better offer going directly to the manufacturer to see what they say regarding protection against such high heat. Or, check out what is used in commercial covers and match that.

Sara Hare said:
Sara Hare's picture

Hello, Im looking at making insulated curtains for our motorhome. I didnt know if you had any knowledge about 100% bamboo thermal fabric?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Sara - So sorry, that isn't a product we've tested or reviewed. 

Cynthia June said:
Cynthia June's picture

Hi Liz,

I just wanted to commend you for all the research you people put into the articles you post.  I am so tired and discouraged by bloggers who are simply posting content to make money and know nothing at all about the products or websites they are "reviewing" on a top ten list, etc.  So many times I've clicked on or tried a product that was in a Top 10 list that did nothing that the blogger said it did!  

Obviously, you and your staff (?) are very knowledgeable and when you don't know something you state so!  

I appreciate this site SO very much, keep up the great work, have a blessed New Year 2017!

Cynthia

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Cynthia June - Thank you for such a nice compliment. We do try very hard to make sure all our articles and projects are relevant. We're lucky to have you as such a loyal follower! 

Anonymous said:
Anonymous's picture

What would be a good material to wrap a thermos around?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

We've had good luck with the Insul-Bright for the thermal carriers we've made. Of course, that's just the inner layer, you'd still need fabric layers on both sides (the thermal batting is the middle of the sandwich). What you use for the outer fabric totally depends on how you'll use the final "sleeve" - it could be cotton, canvas, fleece, vinyl...

Anonymous said:
Anonymous's picture

I have been looking online and I have a question. What is the differnece between Insul-bright Mylar/poly batting and Insul-bright thermal batting. Also could you be more clear on the putside material.

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

There is only one Insul-Bright - it is probably simply called different names from different sources. The "category" it lives in is thermal batting and mylar/poly just more directly describes what it's made of. We don't really have any additional detail on the fiber content other than that provided by The Warm Company: Fiber Content: POLYESTER 93.75% & METALIZED POLYESTER 6.25% - You can also reach out to them directly for more details: https://warmcompany.com/products/warm-home/insul-bright

Anonymous said:
Anonymous's picture

I want my thermos carrier to keep the thermos warmer. Insul-bright does not appear to do that. what is a material that can keep things warm?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

So sorry, but there are too many variables to give you one, definitive answer long distance. You might try using more than one layer and/or layering it something like the Solarize.

PhoenixD said:
PhoenixD's picture

What fabric would work as part of a mattress pad on a hot foam mattress to sleep cooler? I was thinking that it could reflect the heat back down toward the foam bed. This is for my elderly dad who finds the foam mattress helps his lower back pain, but it gets too hot to sleep on with a regular mattress pad. I was thinking of combining it with wool on top. Will that work?

PhoenixD said:
PhoenixD's picture

thanks, I wi check it out--I was sure I had finally narrowed it down and one of these fabrics wold reflect heat one one side only. :-( 

Tracy Chalming said:
Tracy Chalming's picture

Hi there,

Which fabric would you suggest to place between airbed and sheet to insulate against the cold from the airbed?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Tracy - since you'll be sleeping on the surface, you want something quiet, so you'll likely want to steer away from the metalicized products in favor of a thermal fabric. However, for what you describe, a simple wool, down or fleece blanket might be a better, less expensive option. 

Tracy Chalming said:
Tracy Chalming's picture

Thankyou. I'm thinking of sewing a pad into the back of the sheets and wanted something thin to pack down small and light with super duper insulation. I think fleece and wool would need too many layers.

Many thanksTracy

Brittany said:
Brittany's picture

Would this material be good for making gloves for winter?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@ Brittany - of the options listed above, the Solarize would probably be your best option as a thermal barrier for gloves. It is the thinnest and the quietest ... Quiet because the metalicized products can be kind of "crinkly" which wouldn't be great for gloves. You would, of course, layer it with whatever you're using as the main material - wool or fleece or knitted, etc.

Oolio said:
Oolio's picture

Hi, Which fabric would you recommend for making a roller blind/roman blind for a conservatory roof panel? The issues to address are having a thermal barrier to keep some warmth in and heat out in the summer, which (in the winter) would help to reduce a small amount of condensation. The length of each blind would be approx700mm so the thickness of fabric may be an issue if it were to be too thick.

Thank you in anticipation 

Dr. Sam K said:
Dr. Sam K's picture

What would be the best produce to keep extreme cold (-15F) tempertures out while maintaining the heat inside so it doesnt escape?

Freshavocado said:
Freshavocado's picture

An idea is have three layers. on the inside, have something that warms you, wool or something. For the middle have an insulator. and on the outside have something more strong but fancy.

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Dr Sam K - As a home sewing site, we don't really have the expertise to advise on such specialty situations. You'd likely have better luck reaching out to the manufacturer of the products above and/or a site that specializes in heating solutions or even outdoor equipment. They'd have more experience with extreme temperatures.

DL said:
DL's picture

Would this be a good option for a vehicle emergency (Bug Back) bag? I have medication and medical supplies  that i want to include in the bag, but they are sensitive to the extreme elements of heat and cold in a vehicle. 

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@DL - The Insul-Shine or Insul-Fab might be a good choice. That said, we're always a bit reluctant to give a suggestion when your end use involves such temperamental (and important) supplies. You may want to look online and see what commercial options there are out there and then look at their details to see what they use for insulation. Plus, there might not be one thing that will work correctly in both heat and cold. It likely depends on exactly what temperature you need to maintain. Again, we aren't really experts in specialty uses that you describe. 

Brenda said:
Brenda 's picture

I would like to make dog crate pads that reflect their body heat.  What product would work best?

Liz Johnson.Editor.Sew4Home said:
Liz Johnson.Editor.Sew4Home's picture

@Brenda - we haven't tested this situation, so cannot give you a guaranteed result, but the Thinsulate would be a good candidate with which to wrap a pad - you'd of course want some sort of covering over it. You might want to take a look at how the commercial pads are made to see what they use for a cover.

Matt said:
Matt's picture

Which of these is the thinnest and most pliable (in terms of folding over itself)

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