Wanting to avoid dependency on oil, these homeowners built an underground, energy-saving home in 1978. Passive solar is inexpensive and easy-to-implement if the home is situated with excellent southern exposure. Not only do environmentally-friendly structures reduce the need for manmade energy sources, green homes save money.
The home faces south to allow the sun to warm the home during the long, cold winters. Triple glazed windows keep the cold air out and the warm air in. This green home is easy on the environment and even easier on their budget.
The homeowners called the University of Illinois’ extension program to confirm that the depth of the roof’s overhang was optimum for passive solar purposes. Based on the homes latitude, the depth of the overhang keeps the hot rays of the sun out of the home in the summer and allows them to enter the home from October thru March.
Dark brown tile soaks up the suns rays and keeps the home warm on sunny days. Rugs are used to regulate the heat on days when the homeowners want to leave their curtains open but want to keep the home from getting too warm. The tiles will radiate heat long after the sun goes down. Under the tile is a foundation of 4” poured concrete.
A wood burning stove at the back for the 2200 SF home warms the home on cloudy or especially cold days. They have a gas furnace as a back-up but it is rarely used. By burning wood they harvest from the fallen trees on their farm and using passive solar heat, their energy bills are lower than any of their neighbors.
The walls are constructed of 8” poured concrete reinforced with rebar. The dirt pushed against the wall acts as insulation for energy purposes. The subterranean home also keep unwanted traffic sounds at bay.
The sunroom protrudes from the home for more sun exposure throughout the day. It also provides the homeowners with a view of the front of the house. The long windows and sliding glass door are ideal for passive solar applications.
Like a normal house, all rainfall runoff is directed to gutters. Rather than route the water along the exterior of the house and risk seepage, gutters drain into a 6” underground perforated tile. The tile runs along the back and both sides of the home’s perimeter. For optimum drainage, pea gravel up to a depth of 6” was placed on top of the tile before dirt was added. Even during record rainfall during 2009, the house remained watertight.
From the back of the house it is easy to see that only the roof is above ground. To prevent water from entering the home, the homeowners placed 4 inch thick Styrofoam against the concrete wall before lining the perimeter of the home with thick plastic sheeting. Dirt was then pushed against the home to add insulation and protection from the tornadoes that frequent the area.