On one of those bitter cold, windy days, with an intense blue sky and the temperature near twenty, we slip quickly into a car that's been parked in the sun. Oh, how we relish the delicious warmth of that trapped solar energy. We have just experienced the incredible power of the sun this time of year.

With its short wavelength and high energy, sunlight easily penetrates the car's windows. However, once the sunlight hits an interior surface, particularly a dark dashboard or the seats, it is changed to longer wavelengths with lower energy. These longer infrared waves, which still contain much of the sun's energy, aren't powerful enough to get back out through the glass. That solar energy is trapped and it then warms the car's interior.

Acting as a greenhouse, the car has put solar energy to use. We have used this simple principle for over twenty years to heat our house whenever the sun is shining.

During the coldest months in this region, the sun spends most of its time low in the southern sky. It shines on the south sides of buildings. If we put windows on the south side, whenever the sun is visible, it will deliver heat freely into that building. If the building is well-insulated and contains some mass, like sheetrock walls, a slate floor, or a stone chimney, it can easily store some of the sun's energy for the nighttime.

Of course, it's not always cold around here. Sometimes its very hot. Remember? At those times we don't want the sun pouring into our houses.

During the spring and summer, the sun is high overhead when it shines on the south side of buildings. But, during the morning, it shines directly onto the east side and in the afternoon it shines directly into the west windows. So, if we have a bit of overhang on the south side, and fewer windows and more shade trees to the east and west, the sun will pump less heat into our homes in the summertime.

With the correct orientation alone, a properly-sited building uses much less oil, gas, wood or electric heat in the winter and much less electricity for cooling in the summer. Several well-placed trees can provide most of the remaining air-conditioning needs of a solar-oriented house with adequate cross ventilation.

The reduced energy use because of this simple solar solution provides many benefits. The homeowners have lower bills for the life of the house, simply due to its orientation. And the entire biosphere benefits from the much-needed reduction in greenhouse gases, acid rain and radioactive wastes.

All this is common sense information, which has been known and acted upon since ancient times. However, it seems that most of the new houses built today have just a few small windows on the south side, often in the garage, and have lots of windows on the east and west opening into the main living spaces. Every year for the life of these houses, they will need more fuel to keep their residents warm and more electricity to keep them cool, just because of the builder's, architect's or subdivider's failure to consider one of the most basic facts of life on earth - the changing path the sun takes across the sky.

Of course there are also sensual and aesthetic benefits to orienting a house so it welcomes the winter sun. The bright warmth of the sun on a chilly day is as welcome in our home as it is in a car. With a bit of planning, the need for daytime lighting can be eliminated, too, for more savings of dollars, greenhouse gases and radioactive wastes.

In the summer, the pleasure of the quiet shade of a tall tree and the cooling breezes it encourages can be shared with neighbors instead of the air conditioner's hot exhaust and constant roar.

Some mix of arrogance, ignorance and stupidity enables our society to build so many big new houses which ignore the reality of the sun and the wisdom of our ancestors. As a result their owners miss the pleasures of free energy, and pay the increasing tax subsidy, environmental and direct costs for fuel and electricity. The rest of creation suffers from the wastes produced.

This year. investigate the solar heating and cooling potential for your home.

This is Bill Duesing, Living on the Earth

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