Insulating Yourself Is More Efficient Than Insulating Your Home

Insulating Yourself Is More Efficient Than Insulating Your Home

It’s not that high-efficiency, well-insulated dwellings aren’t vital to both saving money and being kind to the Earth. But if you’re trying to stay warm, layering up with long underwear — specifically the newer, synthetic kind — is mathematically more efficient than messing with the heat or walls.

Low-Tech Magazine offers a fantastically geeky read on the thermal efficiency of personal insulation versus household heat. You’ll learn about “clo units”, the measure of insulation needed to keep a resting person comfortable at 21C. You’ll also see that wearing a form-fitting layer of long undies can keep you much warmer, due to the heat generated by thin air layers, movement and other thermodynamics best explained by the author:

According to the US Air Force Survival Book, one layer of long underwear (long pants + long-sleeved t-shirt) equals a clo-value of 0.6, while two layers of long underwear add a clo-value of 1.5. In other words, the clo-value more than doubles by using only two layers. Combine this outfit with a typical business suit (or a similar, more comfortable clothing ensemble), and thermal insulation rises to 2.5 clo, enough to keep a couch potato indefinitely comfortable at a temperature of only 12.7° Celcius (55°F) – far below the common indoor temperatures of today. This clothing ensemble could yield a reduction in energy use for space heating of up to 80 percent.

Old-school, natural-ingredient long underwear is also pretty handy, the article points out, but the newer, UnderArmor-style synthetics seem to do a better job at trapping heat. If you’ve got an under-clothing recommendation, or can’t believe the numbers you’re seeing, let’s hear about it in the comments.

Low-Tech Magazine: Insulation: first the body, then the home [via TreeHugger]


  • Fantastic. I haven’t used a heater in three winters now, going for a fourth. I might add some thermal layers to my shopping list for those really cold days!

  • I would say Merino is much more efficient than the synthetic stuff. I dont have evidence except from experience wearing both in cold conditions and Merino breathes better and doesnt stink up!

  • I thought Icebreaker was a good brand for years, but lately there product is not good at all. The finish of the product isn’t what it used to be and they start smelling really quickly.

    I have a t-shirt from 8 years go from them, works wonders. Doesn’t stick at all.
    One I bought 1 year ago, ‘super-fine’, sticks and lost it’s shape.

    For underwear leggings, I swear by synthetic, they fit better. Falke is selling now in Australia too. There undies are nice too.

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