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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


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.


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.


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, 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


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.



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 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


Comments (188)

susanjodt said:
susanjodt's picture

I'm trying to find an insulation to make a cat bed that will warm-up when the cat is sitting or sleeping on the bed.  Do you have any suggestions?

Sue.B.Sews said:
Sue.B.Sews's picture

I'm doing the same thing, wanting to make self-warming cat beds. I've purchased them from Chewy. I want to start sewing them to donate. 

Solorize might be the answer because it is washable and dryable. I may research it more. 

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

@Sue.B.Sews - The Insul-Bright thermal batting is also washable. Many of the commercial beds also include a layer of foam which can help with heat retension. Dense layers like wool and traditional quilt batting are also options. It's really the cat's own body heat that is doing the warming, so lots of good, dense layering - perhaps with at least one of those being a thermal batting - is going to help trap the warmth. Definitely keep the height on the short side --too much loft, like a polyester fiberfill or a non-dense foam might be soft, but that's more space to warm up and keep warm for a little critter like a kitty. 

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

@susanjodt - I'm not familiar with an insulating material with those properties. The body heat of the cat will naturally make just about any soft fabric warm and some of the insulated battings could help hold that heat for a longer time. You might be better off with a simple heating pad or they do make pet bed liners that you plug in - they are more often used for outside dog houses and such. They are a rubber or plastic coated warmer that is pressure sensative, so when the animal sits on it, the heating is activated. 

Kathy Costin said:
Kathy Costin's picture

I just found your site and I'm fascinated by the wealth of information.  I want to make insulated placemats to keep plates warm at a dinner party.  I envision warming the placemats and putting the plates on top just before serving.  I was thinking of using Wrap-N-Zap because it is microwaveable.  Is this the best choice?  

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

@Kathy - Welcome aboard! Based on what you are describing, it does sound like the Wrap-N-Zap would be a good option. Remember to keep all the other elements of your placemats cotton or other natural fabrics as well -- even cotton thread is a good idea for extra-safe microwaving. 

lsutigerfan0115 said:
lsutigerfan0115's picture

Thank you for the article! If I wanted soemthing to wrap around hot food in a covered dish and keep it as hot as possible - losing as little heat as possible, would batting or fabric be better for that? Would something like Insulate work well for that purpose? Thanks!

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

Isutigerfan0115 - For our cassorole wrap project (link below) we used InsulBright sandwiched between layers of fabric. It works well - although, no fabric/insulation combo is going to be as effective as something like a commercial hot box (like a thermos® type of large container). Another thing to try would be to wrap the dish with two layers of the sandwiched fabric/InsulBright.


lsutigerfan0115 said:
lsutigerfan0115's picture

Thanks so much!! I am looking to make an insulated blanket that can fold up small when not in use with enough insulation to keep, say, a pizza warm from the time it leaves the restaurant till it gets homes. Something with the insulation of a pizza box but can be folded up small. Does your casserole cover have that sort of warming potential?

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

Our casserole cover is designed more for a traditional casserole dish so it isn't a blanket style. For what you want to do and the larger size of item you're wrapping, batting would likely work well or even a fleece blanket. Or - you could even try one of those "space blankets" that are sold commercially - they fold up very small. 

Valle elements said:
Valle elements's picture

Thank you for this article!  I'm building a bnb in Mexico's wine country and want some of the walls of the free standing rooms to roll up so the guests can really interact with the elements.  An insulated material would be better than traditional canvas for climate control i.e. running the AC/heater.  Do you have a material suggestion for this application?  

Thank you,


anne.adams said:
anne.adams's picture

@ Valle elements: Take a look at Warm Window® from The Warm Company. We have not tried this specific product ourselves, but use many of The Warm Company quality products with great success! This is what they say:

"Warm Window insulated shades system will help keep in up to 80% of heat normally lost through windows in winter, and blocks up to 79% of the unwanted solar heat gain through windows in the summer..."


Bettina Tinker said:
Bettina Tinker's picture

I sleep hot and would like to keep my comfy/too warm mattress. Could any of these fabrics be a "cool barrier" so I can enjoy good sleep?

anne.adams said:
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@Bettina Tinker: None of these products are really right for your purpose -- they would likely be noisy, too small or are designed to retain heat. There are products out there that can help you sleep cooler -- cooling mattress pads, pillows and sheets, cool gel mats and even mattresses designed to stabilize mattress temperature. A couple of simple basics are to stick to 100% cotton sheets and bed coverings and avoid memory foam. Do a google search for bed cooling products and you'll find many from which to choose.

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

@Ade - You can see above that we have a few puchase options at the end of each product's description. "A number of sources offer Insul-Bright online, including Fabric DepotJo-Ann and Fabric.com. It's also readily available at many local fabric and craft stores."

Johnb207 said:
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Hi! Someone in my Myspace group shared this website with us so I came to look it over. I'm definitely loving the information. I'm bookmarking and will be tweeting this to my followers! Great blog and terrific design and style.

Liz Johnson.Editor.Sew4Home said:
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@John - Thanks; we're so glad to hear you're finding lots to love!

Patricia Lynn said:
Patricia Lynn's picture

Seeking help for overheated memory foam. My mattress with a memory foam top (i.e., "plush Euro-foam") makes my backside overheat, and the heat wakes me up every night. I wondered if I could put a layer of insulating fabric under (or over) the mattress cover to block the heat radiating from the memory foam. Which fabric would work best? It cannot be a noisy fabric, since crinkling sounds would wake me up. Also, I don't want a carcinegetic fabric, for obvious health reason. (Happily, I know how to sew well.)

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

@Patricia - So sorry, but that is outside our sphere of experience - we've not tested any of these products in anything like your situation. Maybe a mattress outlet would have an idea for you. Memory Foam is known to retain heat, so you'd think the manufacturers might have some options to investigate. 

Duraye said:
Duraye's picture

Looking for a good choice to make an insulated/thermal blanket for pets.  

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

@Duraye - There are a lot of variables in that question in terms of where you'll be using it, what the exterior fabric will be, size, etc. etc. Because a pet blanket needs to be regularly laundered, you might want to opt for Thinsulate - perhaps sandwiched with the Solarize. Even standard layers of batting sandwiched with the Solarize could provide a toasty inner layer. Then.... for the outside, something tough that could withstand the hair, dirt, and claws of pets would probably be your best choice, like a canvas or poplin or similar. 

Rhonda W said:
Rhonda W's picture

Would like to make a fireplace blanket to keep out the cold and wind in the winter when we are not using the fireplace.  Would you have a recommendation for insulating and reflecting the cold?

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

@Rhonda - That isn't a situation we've tested at all, but it seems like the Insul-Shine or Insul-Fab might be a good choice as an interlayer. You'd want to sandwich it between layers of fabric. The type of fabric would depend on the look you want in the room, but canvas might be a good place to start.

Melanie Lewert said:
Melanie Lewert's picture

I have summer/winter blanket that I bought years ago.  One side keeps you warm, where the other keeps you cool.   I'm working on a two season quilt with those same characteristics.   From your article, I'm guessing Solarize might be the best solution.  Do you concur, or do you have a better suggestion? 

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

@Melanie - Based on what you're describing, it does sound like Solarize could be a good choice. Since we've not made a project like the one you're describing, it's always hard to be 100% sure, but it certainly sounds like a good choice.

Craig P. said:
Craig P.'s picture

I am looking to use a stretchy fabric like a viscose or a poly/spandex, but I also want to thermoline the fabric that I am working with. Is there something that I can use that has a slight give and if not maybe a technique that could help?

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

@Craig - Not sure what your project is or the goal for insulating, but just in terms of "flexibility" - of the products listed above, the Solarize and the Thinsulate are likely to do the best job of moving with the type of fabric you're describing. 

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

@wisdom - there is no one answer as there are a huge number of variables in the other elements of your project: size, the exterior and lining fabrics you're using, what type of item you're making, etc. In general, for things like wraps/carriers that help keep a hot dish warm, the Insul-Bright is probably the most popular. And, even with that, you might want/need one layer or multiple layers. 

Karen St. Pierre said:
Karen St. Pierre 's picture

Could I make a bag put pie weights in it and bake in oven  so lift out easy 

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

@Karen - with very specific situations such as yours, we simply haven't done enough testing to give you a definitive answer. The Thermaflec does have a high heat tolerence so it is likely a good option, but you'd really need to do some testing on your own to insure you'll get the results you want. 

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

@PS - You didn't specify which product you were asking about or exactly what type of project you're working on. But in general, for something like a lunchbag or similar, the thermal battings do help keep the cold in. However if the idea is to keep food items cold, the item(s) would, of course, need to start out cold or you'd want to include a cold pack. None of the products above are meant to be used directly against food. You'd need to sandwich the thermal batting between layers of polyurethane laminate or similar (you'd want to research your options online for food safety).

M Chippewa said:
M Chippewa 's picture

Which is best for a diy non electric  blanket  ? Need to keep an elderly lady warm this winter 

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

M Chippewa - For a blanket, we've found that traditional fabric and batting is usually best. The weight and comfort for something like that, especially since she is likely to be indoors keeping warm, is better. Nice thick fabrics such as wool and fleece are always great, layered with standard quilt batting. 

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

@Dudztx: as mentioned above: 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.

Jerome said:
Jerome's picture

Which material would best be suited for sewing into a tent to keep the heat off in the mornings and summer but feels nice and warm at nights when it gets cold and not flammable?

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

Jerome - As a home décor site, we didn't test any of the materials in the situation you're describing, and don't consider ourselves experts in outdoor gear. You might try a couple companies we have here in the PNW that specialize in outdoor projects: The Rainshed and Green Pepper Patterns -- links below. We have no affiliation with either but both are very reputable companies.



Barb01 said:
Barb01's picture

I am looking for a fabric to add to  the painters canvas drop clothes that I am using as drapes... I need a fabric I can sew on that will insulate ...keeping warm in and the winter and hot out in the summer. The drop clothes are are large rings so they can be opened and closed.


Sara44 said:
Sara44's picture

I am converting a cargo van into a camper and wanted to know which fabric you would suggest for insulative curtains that go between the front and rear? Also, would it be okay to sew a more decorative fabric over the insulative one?

stedfast93 said:
stedfast93's picture

Hi. I was just wondering the same in regard to curtains.  I'll be making new ones for the RV we just bought. Did you make a decision yet? I'm looking at the one by Pellon, it's like fleece but reflective. I don't thunk it makes a crinkle sound.  Not 100% sure. I figured I would sandwich it between a backing and the curtain itself. Would love to hear what you came up with. My email is stedfast93@gmail.com. thanks!

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

@ Sara - there are a lot of variables surrounding this question, but in general, if you don't mind there being a bit of a "crinkly" noise when moving the curtains, one of the heavier thermal options would likely be the best - like the Insul-Fab. You can certainly add a decorative fabric for either your top layer or lining layer. Is it best to layer any of the thermal options. You might also want to look into the product Warm Company has that is specifically for windows as another option: https://warmcompany.com/products/warm-home/warm-window

Jay said:
Jay's picture

I’ve been doing a bit of research into this and thought I’d lend my basic knowledge of physics to help people with determining the best product for their application.

These problems are modeled as two zones at different temperature / energy levels separated by an insulating surface. The three methods by which heat is transferred are kinetic energy, radiation, and convection.

The kinetic energy will typically be hot and cold air. The insulating material’s R value determines how much energy is transferred.

Radiation energy is emitted by warm bodies and the sun. The radiation reflecting material determines how much of this energy is allowed to pass between the zones.

Convection is related to the porosity of the insulating material. A porous material may allow air and moisture to pass between zones.

Have fun with your projects! All the best

CharlotteOttilo said:
CharlotteOttilo's picture

Hi Jay, just wondering if you can answer this question. I went to Joann yesterday. I asked for the Pellan product that I could use for making an insulated bag for baby bottles. She sold me Thermalam. In researching(should have done that before I left), I'm not sure if this is the right product. What do you think?  Thanks! 

CharlotteOttilo said:
CharlotteOttilo's picture

Thank you Liz, hope you get this, I keep getting a message that I am spamming.  lol