The Tenhundfelds designed this one-of-a-kind house themselves in 1982, then built it (also mostly by themselves) over the summers of 83 and 84. The house is earth-bermed to the north and a walkout to the south, tucked into a hill on a 23-acre, beautifully wooded site near the Ohio River in Switzerland County. The house is about 1,250 square feet and has 2 bedrooms. Locally harvested and milled lumber was used for the beams, doors, cabinets and part of the ceiling.
The attached, but thermally separated passive solar sunroom stretches across most of the south of the house. The sunroom adds about 320 square feet of living space. The south wall of the sunroom has nine 3'x6' insulated glass panels. There are 4 skylights of same size on the south-facing roof slope. The sunroom is separated from the rest of the house with two very large sliding glass door units. Thermal storage is accomplished by brick in the sunroom, a concrete wall between the sunroom and the rest of the house, and the satillo tile-covered, insulated concrete floor.
The house's and sunroom's cathedral ceilings were insulated to about the mid-R-20s, which was considered radical at that time. (Since then, Indiana has raised its ceiling requirements to R-38!) The concrete walls were insulated with two inches of extruded polystyrene on the outside below ground level and one inch inside from floor to ceiling.
A 15-year-old woodstove is the primary heat source to backup the passive solar heating. Periodically thinning the surrounding woodlands for better tree management provides more wood than can be burned over the winter.
Propane is used for water heating and cooking. The water heater is an instantaneous type with no storage tank, ideal for a weekend residence. A small window AC unit is used during summer mostly for dehumidification.