A Passive Agressive Earth Sheltered House: The Knowns

As y'all know, temperature differences in air have a handy property: warm air rises and cold air falls. I'm pondering how to take advantage of this property in a home. In particular an off-grid earth-sheltered studio located in the gray Pacific Northwest. I have skimmed some "passive" books that might contain strategies and ideas but most such books are focused on solar energy. With approximately 8 hours of sunshine in the last month anything related to the Sun is off the table. I used to be a smart guy capable of solving complex problems, maybe if I take it slowly I can figure something out.

In this blog entry I am going to take the approach taught in high school geometry where one starts out by writing the givens or known information. In a later entry, I will hopefully write out some conclusions.

The three necessary tasks for making a home comfortable are heating, cooling, and ventilating.

The interior temperature is either at, below, or above the comfort zone.

The exterior temperature is either at, below, or above the interior temperature.

Assuming acclimatization and appropriate clothing, the target temperature in the winter is 64 degrees and, in the summer, 72 degrees.

The typical local winter (November through March) high temperature is 48 degrees and typical low is 38 degrees. The typical summer (June through September) high temperature is 78 degrees and typical low is 57 degrees. I'm assuming that looking at only the extreme cases is needed.

All heating is accomplished by burning wood and requires a large amount of oxygen.

The earth-sheltered studio will have a roof insulated from the six inches of dirt covering it. The floor of the studio will be insulated from the ground and be approximately 9' below ground. The earth-sheltered walls will be insulated from the earth. The majority of the walls will be earth-sheltered. There will be one or two windows and one door.

The temperature, say 4', below ground will range from 50 degrees in the winter to 62 degrees in the summer. These numbers are guesstimates.

There will be a natural temperature differential between the floor and ceiling. In the winter the floor will be a few degrees warmer but in the summer the ceiling will be considerably warmer maybe by as much as 10 degrees.

That's all I have for now; I will probably come up with other givens later and will update this page. The next step will be to outline what happens to the home and the air within it during typical winter and summer days.