We’ve recently noticed a new type of insulation showing up in outerwear. Many sites promote it as “NASA-inspired”, and they are not wrong. What we’re talking about here is aerogel, a very high tech and unique insulating material that found its original applications from NASA.
How does insulation work?
Outwear keeps you warm in three ways: conduction, radiation, and convection. Conduction occurs when objects are in contact (heat always moves from warm to cool), radiation is the transfer of heat as electromagnetic radiation (the body radiates mainly in the infrared region), and convection is the transfer of heat through fluid motion (air is a fluid, so wind causes convective heat loss).
Insulation helps slow conduction by trapping air, which has a low thermal conductivity.
Two common measurements of insulation value in outerwear include the insulation weight (in grams) and fill power. Weight is just what you’d expect — the weight of one square meter of insulation. Typically, warmer insulation is heavier. Fill power is the volume one ounce of insulation fills (higher fill is warmer because it traps more air).
What is aerogel?
Imagine a gel (gels are mostly liquid with a 3D solid network to hold them together) where the liquid is replaced with air — that’s aerogel (>98% air). Due to the size of the pores that contain the air, the thermal conductivity of an aerogel is far lower than insulation filled with air. Due to this extremely low thermal conductivity, aerogel insulation can retain its insulation ability even when compressed. This is due to the fact that while you can compress the air out of fibers embedded with aerogel (or in the case of an aerogel sheet, there isn’t much air to compress out), the aerogel itself is not compressed and still provides significant insulation.
The biggest issue with aerogel when it was first developed was that it is rigid and easily breaks into a powder. Since then various advances have given it some flexibility.
While it appears that other companies have made jackets from aerogel, OROS Apparel seems to have the oldest jacket still on the market. They developed what they call SolarCore, which is an aerogel in a polymer sheet. SolarCore is breathable and water-resistant, retains its insulation under compression (something many insulations can’t do), and is very thin and light. Their warmest jacket, the Orion Parka, claims to have been tested in stormy and below zero conditions — I’d say that’s a warm jacket!
PrimaLoft Cross Core and L.L.Bean
Just recently, L.L.Bean announced an outerwear exclusive with PrimaLoft for their new Cross Core technology. PrimaLoft has developed a way to fuse aerogel particles into their PrimaLoft Gold insulation fibers (here’s the patent if you’re curious) — this is called “PrimaLoft Gold Insulation with Cross Core”. Right now you can find this insulation in the L.L.Bean Packaway Jackets and the new line of Ultralight Sleeping Bags (35 °F semi-rectangular, 20 °F rectangular, 20 °F mummy, 0 °F mummy). The ability to retain insulation when compressed is a big plus for a sleeping bag, and not even the current standard, down, can claim this. Also, they seem to be at least half the weight of a comparable down bag (but they compress to a similar size).
Outdoor Research has also announced gloves utilizing a PrimaLoft aerogel technology (called “PrimaLoft Gold Aerogel”) for Fall 2018. We haven’t been able to find much information on these gloves, but they will most likely be unique in their thickness to warmth ratio. Also, from what we can find, it looks like this is a different technology in which the aerogel is encapsulated in a sheet that is not very breathable.
We are excited to see how PrimaLoft builds on this technology as well as how our favorite outdoor brands utilize these two different types of aerogel insulation for the apparel industry.