Customers occasionally ask us why we still use Thinsulate™ insulation by 3M™ in our Koffee Kompanions™ products, considering other “innovative insulations” having been produced since we started our business in 1996. Short answer: Thinsulate™ is the number 1 insulation available for fabric applications, including our French press cozy, takeout cup sleeves, teapot cozy, mug cap, and ice cream koozie. That’s right—every item in our product line still contains the best insulation on the market for retaining heat or cold.

So how do various other insulations stack up against Thinsulate™? Not well! A rank-ordered list of the six most well-known fabric insulations shows Thinsulate™ is the number 1 fabric insulation by far!

The other five are

2. PrimaLoft®

3. Thermolite® Plus

4. Polartec® Fleece

5. Neoprene

6. Insul-Bright®

Why we chose Thinsulate™ for our French press coffee cozy, teapot cozy, cup and ice-cream wraps, and cup cap

Thinsulate™: How it works. Reflects interior heat or cold back into containers (left) while keeping out moisture and exterior temperatures (right). Courtesy of 3M™

First things first: why (after 25 years) Thinsulate™ insulation by 3M™ continues to be the insulator of choice for our entire product line. Thinsulate™ ounce for ounce has one and a half times the warmth of down and at least 2½ times the warmth of other high-loft insulation materials, including those listed above.

Its effectiveness depends on a high “R value” (measure of insulating properties), which varies with its weight or density. Koffee Kompanions™ uses 3M’s heaviest density for fabric applications, 200-weight (about a half-inch thick), to get an R value of at least 2.2 and the most effective heat retention in cozies, wraps, and caps.

How Thinsulate™ works with radiant and conductive heat from containers with either hot or cold liquids inside.

Other features contributed to our decision, as well. Using microfibers that are only a tenth the size of other synthetic insulation makes Thinsulate™ much more successful at reflecting back heat or cold. It also absorbs less than 1% of its weight in water, allowing it to retain its insulating ability even in damp conditions. Finally, it’s made of 50% recyclable material, so the manufacturing process is environmentally friendly.

One can use Thinsulate™ for any kind of project in which you want to keep something warm or cold but don’t want a lot of bulk, such as jackets, gloves, blankets, and—especially important to Koffee Kompanions—cozies, wraps, and covers.

How does PrimaLoft® compare with Thinsulate™ for insulation?

With an R value of 0.81 for half-inch thick insulation, PrimaLoft® Gold (now called PrimaLoft® P.U.R.E.) can’t compete with Thinsulate™ in retaining heat. Thinsulate’s R value of 2.2 makes it at least 2½ times more effective than PrimaLoft® for keeping heat in with cup wraps, mug caps, tea cozies, and French press cozies. Similarly, because Thinsulate™ works equally well when cold or damp, it best retains ice in your cold drinks and ice cream in pint containers.

Does Thermolite® Plus compare to Thinsulate™ in keeping your coffee or tea cozy hot?

When it comes to applications for small products like ours, Thinsulate™ remains the warmest and thinnest insulation material in today's market. Thermolite Plus® consists of one thin fiber and another hollow fiber, which together create an insulating barrier. But Thinsulate™ fibers are about 15 micrometers (0.00059 in) in diameter, which is thinner than Thermolite Plus®. Thinsulate™ is therefore more effective because its fibers are denser and smaller than other insulations. [W]

Thermolite® wasn’t available when we first created our line of Thinsulate™ insulated products in 1996. Now that it is, we won’t consider it because it’s no longer made in the USA. Since 2019, Lycra, Coolmax, and Thermolite operate collectively under the name The Lycra Company and are manufactured in China. [WI]

How about Polartec® fleece? Is it better than Thinsulate™ for fabric insulating properties?

Some crafters have created cup wraps and other covers using Polartec®, so you may see some of these products online, with retailers claiming their insulation is “best on market.”

But Polartec® has an “R value” of just 0.59 for a 300-weight sample, which implies a 200-weight sample’s R value would be just 0.395. That means 200-weight Thinsulate™, with an R value of 2.2, is nearly six times more effective than Polartec® at holding in heat or cold. [ML]

3M's Thinsulate™ insulation works the same general way as Polartec®, but its material also resists moisture and wicks away condensation that forms on cold drink cups and drinks containing ice.

How does neoprene compare to Thinsulate in retaining heat or cold?

With an R value of 0.15 for a half-inch thick sample), neoprene pales in comparison to R=2.2 for 200-weight (half-inch thick) Thinsulate™. Thinsulate™ is nearly 15X better at retaining heat or cold in your French press, teapot, mug, or takeout cup.

Thinsulate™ is different from neoprene in many ways, including warmth, breathability, waterproof capability, and thickness. It has more insulating properties and retains heat better than neoprene. Thinsulate™ is breathable and designed to trap air molecules, but not water, within its layers. So it wicks away moisture and allows water to evaporate. As a result, Thinsulate™ keeps cold-drink condensation from creating rings on surfaces and continues insulating when wet. Neoprene, a polymerized rubber compound, doesn’t breathe.

Does Insul-Bright® compete with Thinsulate™ when insulating hot or cold beverages?

You’ll see some information from cup wrap crafters that suggests Insul-Bright® works for cozies, but the manufacturer notes it is most effective only when paired with cotton batting for hot pads, oven mitts, and casserole warmers. That makes a finished product thicker and bulkier than Thinsulate™-insulated wraps. It also means Insul-Bright®’s R value (heat retention) depends on the thickness of the cotton batting layer rather than on Insul-Bright® alone, which is why the manufacturer doesn’t include an R value in its product literature. Given its individual thickness, we estimate the R value would be similar to PolarTec®, which would make it six times or more less effective than Thinsulate™ insulation by 3M™.

Another disadvantage for Insul-Bright® is its fiber construction. The fiber’s content is 93.75% polyester and 6.25% metalized polyester. These polyester fibers are needle punched through a reflective metalized polyester film, which has heat-reflecting Mylar woven into it. Because of the metalized fiber and film, it can’t be used in a microwave and sounds “crinkly” when handled.

Your best choice for a coffee, tea, or beverage cozy is one made with Thinsulate™ insulation by 3M™

So far, PrimaLoft® and Thermolite® Plus are the closest competitors to Thinsulate™ as thin insulators for clothing and cozy products. But “closest” still doesn’t mean best. These competitors offer some insulation from heat or cold that could otherwise escape from clothing—or from your hot or cold beverage. Like Thinsulate™, both also are hypoallergenic (unlikely to cause an allergic reaction) and are safe to put in a washer or dryer. [SM, WI]

But Thinsulate™ 200-weight insulation by 3M™ remains the number one fabric insulator for hot or cold beverages and ice cream Koozies™, so Koffee Kompanions™ will always use it in all of our products.

Resources

Anon., “Invista,” https://bit.ly/3jmVNXa, July 5, 2021. [WI]

Anon., “Is Neoprene a Good Thermal Insulator?” https://bit.ly/3BpOswf, April 16, 2020. [FAA]

Anon., “PrimaLoft® vs Thinsulate™ Insulation: Which One is Better?,” https://bit.ly/3lpWMWk, July 19, 2016. [PTI]

Timothy Burns, The Differences of Neoprene & Thinsulate, https://bit.ly/3zsGPnZ, September 28, 2017. [TB]

Mitchell Land, The Difference Between Polartec and Thinsulate, https://bit.ly/2WD8tjU, September 28, 2017. [ML]

Sandra Murphy, Thinsulate Vs. Thermolite, https://bit.ly/3jrSXAh, September 28, 2017. [SM]

Rob Simpson, “What Is Thermolite?” https://bit.ly/3EqMuxN, March 2, 2020.

“Thinsulate, Wikipedia.com, https://bit.ly/38nu8z6. [W]

3M Staff, “Product Information,” https://bit.ly/3sWHFaf, 2021. [3M]

Anna Timbrook, “PrimaLoft Vs. Thinsulate: Which Is Warmer?” https://bit.ly/3ytCv6C, November 16, 2020. [AT]

How to stay cozy with Thinsulate™ insulation by 3M™