Hillside House

• An underground house that is built into the south-facing slope of a hillside -- or, in the Southern Hemisphere, into the north-facing slope of a hillside --can have the best of both worlds. Setting the living area back into the hillside makes it well-insulated and soundproofed, but its location on a hillside still allows you to include windows through which light can pour in, and even a view if you are located high enough on the hill. A hillside location also makes drainage easier, which is very important for an underground house. Keep in mind the access of any machinery that you will need when scouting out building sites for an underground house.
  
  

Flat Plain House

• Underground houses can be built on perfectly flat land by situating rooms around a central courtyard that is set into the ground. All the rooms can have large windows or glass walls that face each other around the sides of the central courtyard. A drawback of this design is that you have no view at all; in fact, you can't see anything outside of the house except the courtyard and the sky. A modified version of this design lifts the roof just above the surrounding terrain, allowing you to install skylight windows around the outside perimeters of the house.
  
  

Drainage

• Drainage is important for the preservation of any house, but it is particularly important for underground houses. In a conventional house, you may have moisture problems in your basement, but in an underground house your basement is your house. Before building, the site has to be properly prepared with drainage pipes and gravel. Exterior walls have to be adequately waterproofed before the backfill is put back in to surround them. On a hillside house, the drainage pipes are simply run to a point that is lower than the house. For a house built into a flat plane, a reservoir needs to be dug and filled with gravel to accept any water that may be taken away from the house by the drainage system.
  
  

Advantages

• The ease and low cost of heating and cooling are the primary advantages of underground houses. Virtually no underground houses ever need an air conditioner, and some get by with almost no heat source other than the sun coming in through south facing windows. Underground houses are also highly resistant to tornadoes and hurricanes. They are also very low maintenance in comparison to conventional houses, because instead of clapboards and shingles, all they reveal to the outside world is grass that needs mowing and windows that need washing.