Key Energy Features

Energy efficiency was one of the key design goals for our new house. Some of the energy-related features are:

Passive solar design: An overhang all around the house is designed to block the high summer sun while allowing the low winter sun to shine deep into the house, heating up concrete floors that release the heat later in the day. Most of the windows are to the south to maximize access to the sun and minimize exposure to the north winter winds. High-density insulation in the walls and a 24-inch spacing between studs minimize heat loss in winter and gain in summer.

Earth berm: A two-foot high earth berm around most of the house uses the mass of the earth to minimize heating and cooling costs.

Solar electricity: We generate some of our own electrical power by using a solar electric system with 28 solar panels. On sunny days, if we generate more power than we need, the system sells the excess power to the electric company, an arrangement called "net metering". If we need more power than we are generating, the system automatically buys the power we need from the electric company. If the grid power goes out and it's not sunny, we'll be able to run our basic systems from a bank of batteries (for a few days).

Geothermal heating and cooling: A geothermal system uses coils buried in the earth and a heat pump to provide both heating and air conditioning. In the winter, heat is pulled from the earth to heat water that is circulated throughout the house in pipes within the concrete floors. In the summer, heat is pulled out of the air in the house and stored back into the earth. Although the equipment (a ground source heat pump) uses a fair amount of electricity, it does so very efficiently — they say the pump is "300% efficient", which essentially means (I think) that for every $1 of electricity you spend running the pump, you get $3 worth of heating or air conditioning.

Woodstove: Although not exactly energy-efficient, woodstoves do burn much more efficiently and cleaner than they used to. We have one just because they are pleasant, and it's also a partial backup heat source. Note that if wood is burned cleanly, it has a neutral effect on global warming because the same amount of CO2 that was absorbed by the tree while it was growing is released back into the atmosphere when the wood burns.

Energy-efficient appliances: Most of our appliances have an Energy Star rating. Our Sunfrost refrigerator is very energy-efficient.

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