Passive Solar Design

Passive Solar Design is one of the most cost effective ways to reduce your energy bills.

Before physics, building science, and technology...

A pueblo in Mesa Verde, CO is evidence that even early builders understood the importance of solar orientation.

  1. In the summer, when the sun is high, the south facing overhang of the cave shields the direct sunlight keeping the dwellings cool.

  2. In the winter, the sun drops lower in the horizon, and the direct sunlight penetrates into the dwellings providing heat.

Applying Passive Solar Design to Homes

The way a home is oriented, has a dramatic impact on the heating and cooling of a building. Placing the home on the building site so the majority faces south, is the first step of passive solar design. Most of the sun’s energy comes from the south, so ideally you want your home on an east-west axis with a calculated amount of south facing windows (too much can cause overheating even in the winter) to allow the direct heat from the sun to penetrate and heat the home. In the summer these windows are shaded by appropriately sized roof overhangs.

Other Passive Design Elements

  1. The flooring material installed in south facing rooms is an important design decision. Material with thermal mass that can store solar heat during the day, and redistribute the heat at night. Examples of flooring with thermal mass are clay tiles and finished concrete.

  2. Natural lighting strategies can be used to cut down on the energy consumed for artificial lighting. Windows, skylights, light shelves, and solartubes should all be considered.

  3. Vegetation can assist in passive solar design:

  4. Deciduous trees (loose leaves seasonally) can shade the home in the summer, and allow sunlight through in the winter

  5. Coniferous trees (pines, spruces, firs) can also provide shading, as well as protect the home against wind, snow, and rain.

Summer- Dwelling is shaded by south facing overhang

Winter (same dwelling)- Direct sunlight provides heat