The Importance of Seemingly Simple Choices
The simple choice of window orientation can have large implications for cost, energy use, and comfort, yet these implications are rarely considered. Most attention in building codes is on reducing energy use for winter heating, but in many areas cooling is equally or even more important. Fortunately, design for passive solar heating in winter can reduce summer cooling demand as well, since facing south allows easy solar control in the summer with overhangs. The most common failing of building design is not orienting the house properly, something that has been well understood for more than two thousand years. As the Greek writer Aeschylus noted of the barbarians, “They lacked the knowledge of houses turned to face the sun.”
Fig. 0.1
Besides discomfort, poor orientation is expensive to building owners, society, and the planet. The cost of a 50-square-foot west-facing window in Sacramento California, is calculated to be $40,000 over a thirty-year period if you add up the added air-conditioning cost, the additional utility cost, and the related environmental cost of such a simple choice. If the three million houses built in California since 1980 had been well designed with regard to the simple problem of orientation, we could have reduced the critical summer peak energy demand by 3,000 to 6,000 megawatts at no additional cost. Sustainable design can pay big dividends!
Fig. 0.2. Even when the power is off, a sustainably designed building works well.