hybrid solar house - enertia

David Pogue talks about these Enertia houses that are made of solid timbers of yellow pine laid on each other but the house is also double walled on the north and south sides. on the south side its like a two story glass enclosed porch which heats up during the day. the hot air pushes into the attic which pushes down the cooler northern double walls into the basement. it generates a convection loop that keeps the house about 70 degrees year round. the houses don't need vapor barriers or anything. the yellow pine stores and releases heat. it's pretty cool in that it doesn't use insulation. like all cool housing ideas it ain't cheap though.