Wed December 14, 2011
Earth Notes: Honoring the Sun--Passive Solar Design
Since time before memory people have used sunlight to make southwestern homes more livable. Many of the region’s characteristic cliff dwellings were carefully sited in places that are shaded in summer, but sunny in winter. That allowed natural heating to reduce the need for warming fuels.
Today savvy builders and homeowners are following in that tradition through clever design. Builders of new houses use passive solar design to bring sunlight in when it’s wanted and exclude it when it’s needed. And smart remodeling, too, can reduce heating and cooling bills. The first step in designing homes with the sun in mind is to conduct a solar audit—where, exactly, does the sun travel in relation to the house, and when? That allows the design of eaves that shade windows in summer but allow sunlight in during cold weather. Knowing just how sunlight moves also aids in capturing its heat indoors. A well-placed masonry floor or wall, especially one that’s dark-colored, can store solar energy during a bright winter day, then release it slowly during the cold hours of evening. Some builders and homeowners are even using trombe walls to capture solar heat. A trombe wall consists of glass placed outside over a dark, south-facing wall. Sunlight heats air under the glass, warming the wall—and the house. With smart design, a trombe wall is one of the passive solar features that can make a house more comfortable—and lower heating bills. Next week, join Earth Notes in cooking with the sun.