Underfloor heating: A scientific examination

Happy December everyone! It's officially cold as shit! This means two things in Korea: ondol and kimchi-making. Let's talk about ondol (pronounced on-dole).

Ondol can refer to a few different things, but the one I'm talking about is the modern day heating methods employed in Korean buildings. As I've mentioned before, Korean traditions such as taking off your shoes when entering a building hearken back to the days when people ate, slept, and sat on the floor. The Koreans were also among the first people to heat their floors, back about 1000 years BCE.

The logistics have changed since then, but the general idea is the same: heat the floor from underneath, which heats the air. This concept can be seen, or felt I guess, in all schools and apartments, and even in the heated seats on the subway. 

In my apartment, there's a knob that I can turn to control the temperature of the pipes beneath the floor. Right now, I have it set to just below 20 degrees Celsius, which is about 66 degrees Fahrenheit. A red indicator lets me know when the temperature of the pipes dips below that temperature, turning on the ondol. 

Usually, I leave the knob at 10 degrees (about 50 F) when I go to work, just to get in the habit so the pipes don't freeze. Then, when I get home, I crank it just above 20 so the light comes on and the ondol heats up. After about 20 minutes, the floor is noticeably warm and 20 minutes after that, the air in the room is warmer. Typically, I run the ondol for about an hour, then switch it off before I go to bed. Another teacher at my school runs hers all night, but it gets pretty hot (and expensive) if you run it too long. 

Pros: 

Cold toesies? Just put your feet on the floor!

It heats the room evenly and gradually.

No bulky furnace or other contraption.

Coming out of the shower to a warm floor is one of the best things a foot can experience.

You can do this when you get cold ---

Cons: 

There's no specific heat source that you can stand near for a quick blast of heat.

The heating system doesn't naturally ventilate the room, like central heating does. This can make odors linger and can foster mold growth.

You have to be careful what you leave on the floor. Bad ideas: chocolate, chap stick, butter (I'm assuming...). Good ideas: socks, sweaters, yoga mats.

Pirates:
On an unrelated note: this week I read that pirates wore eye patches to keep one eye adjusted to darkness when going above deck. They would just switch the eye patch back and forth as the lighting changed so they could see easily right away. I tested this concept last night when I got up to go to the bathroom in the middle of the night -- it worked. Try it! Cover one eye while the light is on and your shins will love you forever!