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Thermal Fabrics: Keep Hot Hot and Cold Cold

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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.

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 most versatile thermal batting product we found (and use quite often here at S4H) 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.

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

You can find it at HomeSew.com 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. 

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

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. Sold by the yard, it's 45" wide and machine washable.

When you need insulating as well as heat protection, Iron Quick also comes as a quilted material. This is simply the regular Iron Quick fabric with a 100% cotton backing, polyester batting, and polyester/cotton backing. This doesn't afford a huge amount of insulation, but you could use more than one layer. It is only 42" wide.

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

They can be machine washed but should be air dried. 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 390˚, and like the Iron Quick cloth, does not provide insulation. But also like the Iron Quick, you can find it 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. Again, 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 cool looking 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.

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. It's available by the yard, 60" wide.

Thermolam

 

Pellon makes a 100% polyester interfacing called Thermolam, which is a needle-punched, sew-in fleece with a protective scrim that can provide some warmth. It's available by the yard at a 45" width 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 true insulating and/or padded properties.

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

Fabric.com offers a good price on Thermolam by the yard as does JoAnn.com.

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, 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 it on to keep it 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 microwave-safe designation. 

We found it in a 45" x 1 yard package at JoAnn Fabric. You can also find it online at Nancy's Notions and HomeSew.com.

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 recent Sew4Home projects to get you started:

Casserole Carrier

Insulated Baby Bottle Carrier

Lunch Bag

Picnic Tote

Hot Pads

Oven Mitts

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Comments (105)

blairsong said:
blairsong's picture

Liz, I am wanting to line a curtain that I have in the upstairs of my home in a hallway area as a blocking device for cool air (cold air falls) it gets very warm in this part of my home during the summer months I hung a blackout set there last year and it helped but I want to make it more efficient what do you suggest I hang behind it to provide that extra reinforcement?

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

@ blairsong - that isn't a project type we've tackled, so I don't feel we have the expertise to give you direction when it comes to energy saving! We'd hate to be responsible for not impacting your energy bill in the correct direction. There are also a lot of variables, like the size of the curtain, if it's tight to the floor, etc. Many of the thermal battings are kind of "crinkly" and can be noisy, and they don't come in very large sizes. Check out the Warm Company website (they make many of these products); one of their early specialties was warm window products, which did come in softer, larger cuts. They are likely to have more specific information. 

https://warmcompany.com/products/warm-home/warm-window

Pam B. said:
Pam B.'s picture

Thanks for this great article! I'm sewing Insul-Bright onto the back side of some shades I'm making, and wondering what needle to use? (And although I'm specifically interested in Insul-Bright right now, I imagine an overview of what types of needles to use with these fabrics might be useful to all). 

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

@ Pam - we've traditionally used a universal needle for our projects with this Insul-Bright. We'd switch out from this only if the fabric used with it were unusual or thick. Our research didn't turn up any needle specifics in regards to the Insul-Bright itself. You might reach out directly to The Warm Company to see if they have particular recommendations. 

https://warmcompany.com/

Pam B. said:
Pam B.'s picture

If universal needles work for you, and the company seems to have no indication you need a special needle for it, I think I'll go with that. Thank you so much for your reply! 

EmoGirl said:
EmoGirl's picture

Hi can you plz tell me the best insulators and the best coductors (fabrics) and how they "work" ?

I also want to know the difference of these fabrics

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

@ EmoGirl - I don't have any specific information other that what's given above about the general way they work and the differences between the ones we reviewed at the time of the article. But, if you have a specific useage question, I can try to point you in the right direction. 

Sara M. said:
Sara M. 's picture

I am attempting to make a suitcase or travel bag thermal. I am not trying to get anything hot or cold persay, but manily to keep fresh and from going bad.. I am trying to store cosmetics ( I sell skincare products and make up) for easy travel. 

Thank you. 

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

@ Sara - That's a unique use we don't really have any experience with. My question would be how much airflow is required (if any) to keep your projects fresh. I just don't know that answer to that. I would suggest reaching out to your product manufacturers to find out what they use to keep their products fresh when shipping and/or storing. 

Rob hughes said:
Rob hughes's picture

Hi I'm looking for a heat reflecting material that can stretch, is permeable to water and can be stitched to make clothing any ideas?

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

@ Rob - that's a tall order. I don't know of anything that fits all those criteria. 

Steffanie said:
Steffanie's picture

I'm looking for something conductive, not insulating.  I am making an electric blanket out of carbon fiber tape for the heating elements, and I need something to conduct the heat into the spaces between the elements evenly.  Any Ideas?

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

@ Steffanie - I'm sorry but that is quite a specialized use that we don't have any experience with. I'm not even sure where to suggest you look for an answer. Working with carbon fiber tape is rather unique; you'd definitely want to local someone who has tackled the process before. Perhaps a company that specializes in making outdoor equipment? Again, sorry to not be able to be of more help. 

Courts said:
Courts's picture

hi, I'm making a cooling vest for my son, special ice packs that aren't as cold as real ice so no burning of the skin, but I'd like to insulate between the ice pack and the fabric to keep the cold heading in towards the body rather than being lost to the outside, I'd love to know your thoughts which product might be best for this please?

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

@ Courts - that is a use we haven't come across before. As mentioned below in another recent comment, the main concern for any kind of garment may be the "crinkly" noise of many of the products that are best for creating a thermal barrier. The softer fabric-type options shown above are more for heat protection or for warming. There is a new product from Fairfield called Solar - again, I just recommended this to another commenter as something that could work in situations where weight and noise are issues. We haven't tested it yet, only seen samples, but it is very thin and not noisy. You can read more about it here:

https://www.fairfieldworld.com/store/category/solarize-liner-fabric-craf...

Courts said:
Courts's picture

thanks for taking the time to reply Liz, I'll have a look at that link 

Erik said:
Erik's picture

 I'm looking for an insulating fabric that will prevent conduction and provide a bit of insulation. When camping people use pads to isolate from the ground because  the down or other insulating material in the sleeping bag will get compressed and won't insulate as well and the ground will suck the heat from you. I don't need the pad because I'll be using a cot, so don't want to have to carry the bulk and weight.  I could use a reflective emergency blanket under the sleeping bag, but they're too crinkly and noisy.   Do you think one of these fabrics would work?

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

@ Erik - From a insulating and comfort standpoint, the Insul-Fab or Insul-Shine would both work. However, both are going to be bulkier and heavier than a reflective emergency blanket, so may not be your best selection. I don't know of anything that's thinner or lighterweight than those space blankets. Unfortunately, just about anything with that reflective surfuce is a bit noisy. Fairfield does have a new product that is not quite so "crinkly". It's brand new, so we haven't made anything with it yet, but have handled it and it is much quieter: 

https://www.fairfieldworld.com/store/category/solarize-liner-fabric-craf...

Terry B. said:
Terry B.'s picture

Hi, 

Thanks for the article. I do have a question that I was hoping you might be able to answer. I was thinking of making a sort of tent/liner for the bed of my truck, which has a hard top on it. I dont need it to be waterproof/windproof, I just need it to retain heat. I would like to use this in the winter time to sleep in on overnight trips to ski resorts. I was thinking of using canvas and some other insulation material. Do you have any suggestions?

Thanks in advance!!

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

@ Terry B - I'm afraid that is a very specific use for which we simply don't have any tested experience, so I wouldn't feel comfortable making a strong recommendation. I'd suggest looking at retailers who are more targeted to the outdoor market and therefore might carry the type of materials used for outerwear and/or sleeping bags and such. I've included two links below for retailers in our PNW area: 

The Rain Shed: http://www.therainshed.com/

Green Pepper: http://www.thegreenpepper.com/

Frances R. said:
Frances R.'s picture

I'm looking for a material that is sewable and yet waterproof. I would like to make wine bottle holders to include a chilled/cold bottle of wine to give as a gift.  I don't want the condensation of the chilled bottle to seep through and wet the outer fabric.  I thought Insul-Shine or Insul-Fab might work but I don't believe they are waterproof, are they?  What would you recommend?  Even if the material is not insulated is fine, I can easily insulate it with something else, I just need it to be waterproof.  Thanks so much!

Anna123 said:
Anna123's picture

Hello Liv!

My daughter is doing a project for her science fair and needs a fabric/s that can cool down/let out heat quickly, but also warm up/retain heat depending on the situation outside. She's thinking about sewing these fabrics onto the inside of her clothes that would be touching your body. Which fabric would you recommend using as it should probably also be quite comfortable since it would be on the inside? Do you think there would be a better way for her to do this? Thanks for the help!

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

@ Anna123 - We don't do much here at Sew4Home with garment construction and so we haven't tested any of these fabrics in the situation you are describing. It sounds like she would need something more like a wicking fabric that you might find in outdoot wear, such as a Polartec. There is a company in our area called The Rain Shed that offers a huge selection of outdoor fabric, you might have her search through their website for the various Polartec options: http://www.therainshed.com/ (search the Fabric/Swatch Sets category). Gotta love those science fair projects 

Carlos thomas said:
Carlos thomas's picture

Hi,

I Am looking for a  material that would keep water cool for a small period of time, but also would be warm to the skin at same time.

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

@ Carlos - without knowing the actual project, fabric to be used, and other specifics, we can't give you a guaranteed answer. None of the fabric options above are waterproof, so they cannot hold water directly. The water would have to be in a container - so the container itself will also be a factor. The Insul Bright is what we often use for projects where we want to keep a baby bottle warm or a water bottle cool. You could experiment with that as an initial choice. If you need more warmth on the side that touches your skirn, you'd want to experiment with additional layers of batting, fleece or other fabric to layer with the thermal batting. 

John said:
John's picture

I'm looking for a material that is fairly easy to cut and sew that can be used to keep things from freezing over night, or better yet a few days or more.  The items I'm looking to insulate are metal containers containing various water based liquids, items that would not be kept outside but instead in various structures and/or vehicles.  Can you help with this, and do you know if any of the above mentioned materials, or something else for that matter, could be used in this way and what kind of effectiveness they would have??

Thank you.

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

@John - Our site is dedicated to sewing and craft projects, so I'm sorry, but we don't really have any information about how these materials perform in the situation you're describing. You'd probably be better off taking your question directly to the manufacturer (Warm Company makes the majority of these, but there are links above to research all of them). You might also ask at a local farm feed & seed store if you have one n your area - they would have experience keeping animal water liquid in the cold. Or, a specialty company that deals in outdoor equipment might have suggestions based on what hikers use. One company we like in our area is The Rain Shed: http://www.therainshed.com/

John said:
John's picture

Hi, Liz.

Thanks for the feedback and the input.  I'll do more research and see what I can find out.  What I'm looking for is something that can be sown to accomplish what I mentioned as it needs to be very portable but not a space-hog.

Thanks again. 

Susan J said:
Susan J's picture

Hi my question is different. I would like to make a heat reflective pad for a dog kennel. would you use any of these inside? thanks for advise.

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

@ Susan - it depends somewhat on what fabrics you plan to use for the exterior as well as what you plan to use as a "filler/cushion." We haven't made anything exactly like you've described, so as with other project-specific questions, we can only provide a best-guess. The Insul-Fab above would likely be a good option. Another new product from Fairfield called Solarize is another idea - it's thinner and very flexible so would be a good option if your pad is going to have a foam core - the Solarize would be super easy to wrap. Here's a link to Fairfield: https://www.fairfieldworld.com/store/category/solarize-liner-fabric-craf...

Adil said:
Adil's picture

Hi, Great site and loads of used information. I am looking to create a cloth cover for the radiator in my sons room as it can't be turned off without turning all the heating in the house off.

Which of the materials mentioned in your article would you recommend for this? I wouldn't want all the heat to be cut off though so would want something that does let heat through to an extent to allow the room to warm up  without getting too hot. 

Hopefully that made sense! Look forward to your response. 

Regards, 

Adil

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

@ Adil - we actually get quite a few questions similar to yours. It's hard to answer completely because it's almost more of a design question than a materials question. I hate to give too specific information as I would worry a bit about any type of cloth covering left in place on a hot surface for an extended period of time. In older buildings, I've seen radiator covers made of wood or metal -- kind of like a ventilated box. No matter what you use, it seems like some sort of "frame" would be necessary so the fabric doesn't sit directly on the radiator. Once you figure out the design part, the Insul-Shine product may be your best bet as it's meant for more "industrial" applications. 

Tabatha R said:
Tabatha R's picture

Which of these, if any, would you recommend for lining curtains to help insulat against the cold? Thanks! :)

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

@ Tabatha R - see my answer below to your initial comment.

Tabatha R said:
Tabatha R's picture

Which of these, if any, would you recommend for lining curtains to help insulat against the cold? Thanks! :)

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

@ Tabatha R - insulated windows are a different ballgame - but Warm Company, who makes many of the options above, is the pioneer in that game. They built their business on it and they still produce the top products under their "Warm Window®" brand. You can check it out here: https://warmcompany.com/products/warm-home/warm-window

candida said:
candida's picture

Is it possible to use scraps of insulbrite and piece them together with a satin stitch?  I have so many left over pieces when cutting 8x8 pieces

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

@ candida - we haven't tried it, but it sounds like it could work. Depending on the density of the satin stitch, you coud end us with a ridge or a "wavy" effect on the finished piece that could show through on a project. In this case, you might want to consider adding a thin layer of batting over the Insul-Bright to disquise that. 

Leia said:
Leia's picture

If I am making a rain jacket, and I want to put in a thermal fabric lining, what would you suggest I use?

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

@ Leia - We're not really garment sewing experts here at Sew4Home, so we may not be your very best resource. That said, I'd say you probably want something lightweight with some water repellent properties. I think probably the Iron Quick or Thinsulate would be best. You might also want to check out The Rain Shed - they specialize in supplies for outdoor clothing and gear. http://www.therainshed.com/

Ms E said:
Ms E's picture

Could the Wrap N Zap be used for oven mitts and pot holders? My local department store has it on clearance 

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

@ Ms E -- I don't know if the the Wrap N Zap would have the heat protection you'd want for mitts or pot holders. Because WNZ is microwave safe, they removed all the metallic fibers so it is essentially just a safe, 100% cotton batting. You'd need a lot of layers to have it work well for hot mitts or pads. The thermal battings, like Insul-Bright, are much better for this use. 

Kim of Keswick said:
Kim of Keswick's picture

What a great page of info and great thread! Thank you very much for providing it :)

Does anyone have any recommendations for my dilemma? My gas golf cart seat gets very hot due to the motor that's located below the seat, and hot air escapes at each side of the seat as well, ouch! So, I'm thinking I should make a blanket that will cover the seat and extend past the sides so I can enjoy my ride for longer than 20 minutes. I did remove the cover at the back of the motor to allow heat to escape but it's not good enough. Thank you :)

SmitDog said:
SmitDog's picture

Look at a Welder's blanket.  Rated for nearly 1100 F.  Comes in a 4' x 6' sheet.  

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

@ Kim of Keswick - that's quite a challenge. I think I'd be a little worried about anything fabric hanging loose next to the heat of the motor. You could certainly make a seat cushion that would help out there. For the sides, it might be better to consider havving a shop look at the possibility of creating a shield for either side of the motor, out of a heat resistant plastic or similar, that could act like a flange to direct the hot air down and towards the back. 

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

@ Elizabeth - We didn't recommend any 110" fabric above. We don't have any sources for this width - you might need to research that option with a commercial provider.

Elizabeth said:
Elizabeth 's picture

I am looking for a fabric to use as a thermal lining in curtains. What do you suggest?

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