Posted By ooopie on 05/27/2008 2:24 PM
As I understand, the deep earth provides a fairly constant temp. thermal mass, say 55 degrees. Even so, in the winter I like my house closer to 70 degrees, and would not want the earth sucking up the heat from my house. Therefore, I would want to insulate the house from the earth that is sheltering it, which seems to somewhat negate the whole idea in the first place. The benefits of Earth sheltering are: The constant Earth temperture(assuming that all parts of the Earth sheltered structure are below the frost line), and the elimination of Air Infiltration. Thermal Mass plays no part in these benefits.
I can understand how the earth keeps things cool in the summer, but would it still have that effect if it was separated from the house with lots of insulation?
Is it possible to get comfort and energy efficiency in both the summer & winter (I'm in the northeast) using earth sheltering?
Do I choose insulation or thermal mass? Can I have both? Basically what Earth sheltering does, is reduce your Delta T, to lower that you would have with exposed walls. The Earth, using your example temp, is always 55°. So, you have a year round constant Delta T of 15°. Compare that to winters in the NE where the temp could be 0° and having a Delta T of 70°! Insulation or Mass? No question, Insulation! You could incorporate some interior thermal mass if there is a way to charge it(South facing windows). And, you should have only one one energy cost: Heating. Over time, with constant ground temps(and no external heating), the indoor temperature or your structure will be the ground temp(55°). No A/C needed.
Good Luck! |