Since heating is usually a household’s largest expenditure of energy and the cost is low, insulating your house is one of the most cost-effective conservation techniques around. An even cheaper option is to insulate yourself, but how much good can that possibly do? We don’t often think about our clothing as insulation, but as long ago as 1946, scientists have examined the insulative value (similar to the R-value of house insulation) of clothes, which allows us to figure out what impact it would have.
These researchers created a scale that allows you to figure out your comfort level based on air temperature, activity level, and clothing. Their baseline, 1 ‘clo’, is the amount of clothing a normal person would need to wear to be comfortable sitting around at 70 degrees. 1 clo is the equivalent of wearing a business suit with normal underwear. To figure out the clo value of an outfit, you just add the clo values of each individual item.
Some common clo values are 0.1 for a short-sleeved T-shirt, 0.2-0.4 for a sweater, 0.25-0.35 clo for pants, and 0.22-0.77 clo for a long skirt.
For every 2 degrees Fahrenheit, you need 0.18 more clo to be comfortable (or you need to be more active). A pair of extremely insulating long underwear can be purchased for $25 and provide about 0.36 clo, which would allow you to drop your thermostat 4 degrees! Depending on where you are and what you’re heating with, that could save 15% on your heating bill.
I had a hard time believing those numbers, but I recently got a good pair of long underwear and they’ve made a huge difference in comfort. That makes it pretty clear that insulating yourself can have a huge benefit, especially if you’re currently wearing just a T-shirt and slacks!
How can something as simple as long underwear be so efficient? Air is a good insulator, so keep still air near your body helps insulate you tremendously. Your body is already producing heat too, so all you have to do is trap it rather than using a lossy process like a heat exchange to produce heat. Best of all, you only have to hear the small area right around your body rather than a whole room or even a house.
Last year, my biggest problem was keeping my hands and feet warm. Since I primarily work from home, I had to have warm enough hands that I could type comfortably. Luckily, I’ve found that keeping the rest of your body warm keeps your hands warm too, even without gloves! When your head and torso are cold, your body adjusts by drawing heat away from your extremities. Warming your head and torso mean that your body leaves them alone and your hands and feet stay comfortable even when it’s well below 60F.
If you’d like to learn more about clos, I highly recommend the article in Low Tech Magazine that introduced me to the concept and the clo numbers I listed above (and more)!