Alternative builder Clarke Snell promotes passive solar design for homes, a technique that saves energy and reduces pollution.
Illustration by Dave Channon
The angle of the sun’s arc through the sky is lower in winter than in summer. Passive solar design takes advantage of this cycle to capture heat in the winter and block it in the summer.
In a climate with cold winters and moderate summers, houses that are long and thin on their east-west axis are best because they expose more wall surface to the south, where it will be warmed by the sun in winter.
In a climate with mild winters and hot summers, compact houses with a northern orientation are easier to cool than long, thin houses.
South-facing windows take advantage of the sun’s position during the winter to allow in a maximum amount of light and heat.
Flowering vines above the patio of this California home are just getting started in the spring. By summer, their rapid growth transforms this area into a cool, shady spot. In winter, the vines die back and allow more of the sun’s heat in through the windows.