Aerogel in clothing: how the thinnest insulation works
Aerogel is a solid made mostly of air, about 99.8% by volume, locked inside a nanoscale silica network. The tiny pores stop air from moving and carrying heat, so aerogel insulates well in very thin layers. In clothing it is usually bonded into flexible blankets or composites, which suits gloves, boots and slim jackets, though breathability, durability and cost remain trade-offs.
What is aerogel?
Aerogel is made by removing the liquid from a gel without collapsing its solid framework. The result is an open, sponge-like network with pores far smaller than the width of a hair. NASA's Jet Propulsion Laboratory describes silica aerogel as 99.8% air and chemically the same as glass, yet about a thousand times less dense.
JPL's record-setting aerogel weighed 3 milligrams per cubic centimeter and was recognized by Guinness World Records as the world's lightest solid. Its cloudy, translucent look earned it the nickname solid smoke. NASA used aerogel for thermal insulation on the Mars Pathfinder mission.
How does aerogel insulate so well?
Most insulation, from down to fleece, works by trapping air. Still air is a poor conductor of heat, so the job of an insulator is to stop that air from moving and to limit the solid paths heat can follow.
Aerogel takes this to an extreme. Its pores are so small that air molecules collide with the silica walls more often than with each other, which suppresses heat transfer through the gas. The solid network is also extremely sparse, leaving few paths for conduction. NASA Spinoff describes aerogel blankets as providing three times more insulation than the best fiberglass.
How is aerogel used in clothing?
Pure aerogel is brittle, so apparel uses it in composite form. Aspen Aerogels, working with NASA, developed flexible aerogel blankets that can be cut with conventional textile tools, including scissors. NASA Spinoff lists uses in footwear, outdoor apparel, high-altitude climbing boots and insoles for ultramarathon runners.
Apparel brand Oros moved from fiber-blanket aerogel to a proprietary flexible polymer composite it calls Solarcore. According to NASA Spinoff, its jackets and snow pants use 3 millimeters of insulation, and the line has extended to gloves, leggings, base-layer shirts and knit hats.
Aerogel vs down: which is warmer?
Down is exceptionally warm for its weight because its clusters loft up and trap a thick layer of air. Its weakness is compression: sit on it, squeeze it under a pack strap or wet it, and the loft and warmth drop. Aerogel composites are warm for their thickness and hold their structure under pressure, which is why they appear in boot soles, gloves and knee areas.
In practice the right choice depends on where the insulation sits and what it has to survive.
| Property | Aerogel composite | Down | Synthetic fill |
|---|---|---|---|
| Warmth per thickness | Very high | Moderate (needs loft) | Moderate |
| Warmth per weight | Good | Very high | Good |
| Under compression | Holds structure | Loses loft | Loses some loft |
| When wet | Depends on composite | Loses much of its warmth | Keeps more warmth |
| Breathability | Often limited | Good | Good |
| Cost | High | Moderate to high | Low to moderate |
What are the downsides of aerogel clothing?
Early aerogel apparel ran into three problems that NASA Spinoff documents in the Oros story. Aerogel particles tended to flake out of fiber blankets with movement, so performance dropped over time. Silica aerogel also draws moisture on contact and can dry out skin, which forced early designs to fully encapsulate it.
Encapsulation solved the dust and dryness but reduced breathability to virtually zero, according to the same account. Newer composites aim to restore breathability while keeping structure, though buyers should still expect a different feel from down or fleece.
Cost and stiffness also matter. Aerogel composites are more expensive than common fills, and thin, stiff panels can limit how a garment drapes and moves.
Durability through washing and repeated flexing varies by composite and is not yet as well documented as it is for down and synthetic fills. Follow the care label closely, and look for independent reviews that describe performance after a season of use.
Is aerogel the future of warm clothing?
Aerogel is best seen as a specialist material rather than a universal replacement. It shines where space is tight and compression is unavoidable: gloves, footwear, slim jackets for work or travel, and panels under straps or harnesses.
It also works alongside other technologies. A 2023 modeling study of cold-protection garments compared an infrared reflective layer with aerogel material and found the reflective layer the more effective of the two methods studied, a reminder that radiant heat loss matters as much as conduction. Thin insulation, a reflective layer and a heat source together can do more than any one alone.
If you are always cold or have cold-sensitive hands, better clothing can help comfort, and a clinician can help rule out underlying causes.
Key takeaways
Silica aerogel is about 99.8% air and is recognized as one of the lightest solids.
Nanoscale pores suppress heat flow, so aerogel insulates well in very thin layers.
Clothing uses flexible aerogel blankets or composites, such as 3 mm Solarcore insulation.
Aerogel holds its structure under compression, which suits gloves, boots and slim layers.
Breathability, durability and cost are the main trade-offs.
Frequently asked questions
Is aerogel clothing warmer than down?
Per millimeter of thickness, aerogel composites insulate very well and resist compression. Per gram, lofty down is often warmer. The best choice depends on whether thinness or weight matters more.
Is aerogel safe to wear?
Apparel uses aerogel bonded into blankets or polymer composites and enclosed in fabric. Early designs were encapsulated partly because raw silica aerogel can dry out skin on contact.
Why is aerogel clothing so expensive?
Aerogel is costly to manufacture, and turning it into flexible, durable composites adds more steps. Volumes in apparel are also small compared with common insulations.
What is Solarcore insulation?
Solarcore is Oros's flexible polymer composite containing aerogel. NASA Spinoff reports it is used at 3 millimeters in jackets and snow pants and has extended to gloves, hats and base layers.
Does aerogel insulation breathe?
Breathability depends on the composite. Early encapsulated designs barely breathed, while newer composites were developed specifically to improve breathability.
Related reading
Sources
Guinness Records Names JPL's Aerogel World's Lightest Solid, NASA Jet Propulsion Laboratory
Aerogels Insulate Missions and Consumer Products, NASA Spinoff
Aerogel Insulation Makes Thinner, Warmer Outerwear, NASA Spinoff
Development of Infrared Reflective Textiles and Simulation of Their Effect in Cold-Protection Garments, Applied Sciences (MDPI), 2023
About HEATJAC. HEATJAC is a thermal architecture company founded by an anesthesiologist. We design patented garment systems that capture, conduct and broaden warmth across the body, and we publish this knowledge hub because the science of staying warm should be public. HEATJAC products are not medical devices and are not intended to diagnose, treat, cure or prevent any disease.