Professor of architecture at the University of Texas at Austin
In the summer of 1999, I received a call from Laura Bush. She and then-governor George Bush wanted a design for a house that would blend into the landscape of an extraordinary piece of land they had just purchased in Crawford, Texas. We talked at length about environmental systems, and Laura was clear at the outset that they wanted to do everything possible to protect the land. It is exceptionally beautiful, with deep bluffs, streams and stands of native live oak.
The house is designed to use a quarter to a third of the energy of a normal house its size. With some modification, it could run entirely off the grid. There are dozens of features that contribute, including rainwater-collection and wastewater-treatment systems, which recycle water for irrigation. We installed a geothermal cooling and heating system to cut down the biggest energy drain for houses in Texas: air conditioning. A closed pipe of water runs to underground wells that are at a constant temperature. In summer, the air in the house warms the water in the pipe, which then gives off its heat underground. In the winter, the same system brings heat to the house. It also heats all of the home's hot water. We used "low e" glass, which cuts transmission of heat, and designed the house for easy cross-ventilation. The roof is galvanized aluminum to reflect sun. And we placed the house east of a fantastic stand of oak trees to shade it from the afternoon sun in summer. The house has overhangs on all sides, extending 10 feet out. During the summer, when the sun is high in the sky, these overhangs block sunlight from streaming into the house and heating it. In the winter, when it is lower in the sky, the sun shines below the overhangs and warms the stone walls and rooms. This is actually an old principle used in Native American cliff dwellings. These dwellings are set beneath rock overhangs facing south, so that they heat all day long during the winter, but receive no direct heat from the sun in the summer.
There's another advantage of the overhang. It forms a porch all the way around the house. At the end of the house, the roof extends quite far. When it rains, it makes a room of water, with rain on three sides (the rainwater is collected at ground level). On the fourth side is an outdoor fireplace, so you can be outside even on a cold, wet day, enjoying a fire.