Most educated people today realize that we have been frying the planet with unsustainable practices in building, in transportation, in almost everything we do. Many would build an efficient house if they realized how easy it would be, if it didn’t add that much to the cost, and if it would not have to be ugly.
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Having taken courses through the Northeast Sustainable Energy Association, I knew it was possible to go much further than most people realize in the realm of energy efficiency. Indeed, a house can produce its own energy. With global warming and climate change in full assault, it is possible to demand a house that does that. It is not that hard to do. In simplest terms: Design a house in such a way that a reasonably sized solar system will provide all that it needs.
Confronted with the task of designing and building a house for my wife, Tori, and myself, I set myself the goal of doing that.
Ninety feet long, but only 22 feet deep, with the long south-facing axis mostly glass, there is no need for electric lighting in daytime in any of the main rooms, and even on the coldest days of winter the house will be above 80 degrees with no auxiliary heat if we allow it to go there.
Bathrooms, hallways, and storage are on the north. Because north-facing windows are a solar liability, they are just large enough to provide cross ventilation and are high on the walls where heat gathers. They are electrically controlled so it is easy to take advantage of good weather and avoid using powered climate control.
All the glass on the south side of the house would make it unlivable in summer if it weren’t shaded. Electrically controlled awnings shield the glass in summer to prevent heat gain. We found it just as easy to push a button and drop the awnings as it would be to turn on the air-conditioning, and that eliminates a lot of CO2 in the atmosphere.
Step one in a sustainable house is tight building, no air leaks, and very efficient insulation. Foam insulation inside the stud spaces seals every crack in the envelope. Two inches of Styrofoam as a base for the stucco on the outside of the sheathing interrupts the conduction of heat through the studs in the wall. And earthen berms with insulation outside the foundation are employed to varying degrees on all sides of the house. This stabilizes the temperature inside the envelope to a point where a very small heating, ventilating, and air-conditioning system can keep the temperature within acceptable range.
People worry that a house that is too tight is unhealthy, and that is a reasonable fear. But now we have heat-recovery ventilators. These appliances provide constant ventilation with minimal loss of heat by way of a heat exchanger that transfers the BTUs from outgoing stale air into a separate stream of incoming fresh air.
The heating and air-conditioning are provided by Mitsubishi air-to-air heat pumps, which are powered by electric