There's a surprising amount of earth architecture in Germany. The walls are your storage ... not enough to last all winter, and not enough to make your house ac

There's a surprising amount of earth architecture in Germany. The walls are your storage ... not enough to last all winter, and not enough to make your house actually "warm", but enough to provide a baseline that smooths over energy availability issues. Of course, it works even better with higher levels of insolation, since the exterior surfaces of the walls receive more energy during the day.