Mrs. UC: "I'm cold."
UC: "Put on a sweater."
Math time. Lowest temp: 32 degrees, Highest temp: 128 degrees. 128-32=96. 96/2=48. 32+48=80. So it stands to reason, even though I haven't measured, that the mean temperature of the dirt is 80 degrees. I have measured the temperature of our well water, which comes from a depth of 547 feet. It's 92 degrees.
Quick stats on the UC Mega-Complex:
- Roof: 12" thick concrete, 6" styrofoam insulation, 3' dirt.
- Back Walls: 12" thick concrete, 3" styrofoam insulation, dirt-bermed.
- Front Walls: 12" thick concrete, inside 3-5/8" steel studs/fiberglass insulation, outside 6" steel studs/fiberglass insulation under Densglass/1-1/2" stryrofoam insulation/stucco.
- Floor: 5" thick concrete poured over 1-1/2" styrofoam insulation.
In 5 years of living underground, we've never used the heat. 74 degrees is as low as I've seen the inside temp go. In the summer we use air-conditioning, of course, because the flywheel slowly creeps up from the mean temp of 80 without it.
Two things affect comfort in a home, air temp and structure temp. If the air temp is just right but the walls are cold, you will feel cold. If the air temp is just right but the walls are hot, you feel hot. So most people crank the A/C one way or another to feel comfortable. Here, we keep the A/C set to 78 degrees in the hot months. Trying to chase the perfect air temp is futile in an underground home. I can open the windows at night and drop the air temperature a few degrees, but the second I close the windows the temperature goes back to what it was. The flywheel just won't budge easily.
Posted by Dave.