Implementing solar design principles can slash heating and cooling bills, reducing the size of the renewable energy system you’d need. This article, the first of three, covers siting, orientation, building shape, and room placement.
Solar installer Bristol Stickney wistfully remembers passive solar conferences in the 1970s that drew hundreds of building tradespeople—all excited about building houses that derived a big part of their space heating from the sun. He had to look only as far as Mesa Verde, the spectacular Pueblo settlement in southern Colorado, to see how long passive solar has been in use. Those solar advocates of 40 years ago thought the ideas were finally making it into the building mainstream.
But passive solar design never reached its full potential—politics, cheap utility energy, and missteps by early passive solar practitioners helped cause the passive solar movement to lose its zip. Now, when people talk about “solar,” says Stickney, an industry veteran based in Santa Fe, New Mexico, they usually mean rooftop PV modules that produce electricity, not the building practices that allow homeowners to reap free heating from the sun.
Despite its second-class status, passive solar works—and well. The passive solar vanguards were correct—even in northern climates, a well-designed passive solar house will reduce a home’s energy costs. And unlike technologies such as ground-source heat pumps or PV arrays, many passive-solar features add little or no construction cost.
Passive solar design includes practices that help keep buildings cool in summer as well as warm in winter—something that early solar designers struggled to master. “A good passive solar house provides comfort no matter what the weather,” Stickney says. “In the past, a lot of passive solar houses had too much glass and would overheat when it was sunny and the weather was mild. It would get too hot in the spring and fall, but not hot enough in winter.”
Designers have since learned how to deal more effectively with that challenge. But any good design is site-specific, since each building site has its own weather and temperature patterns, as well as a unique topography that affects heating and cooling. A passive solar house designed for the high deserts of New Mexico might be pretty uncomfortable if transferred to coastal Maine. The house design must match its site.