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If you’re planning on building a home and are interested in realizing the most bang for your energy efficiency buck, you’d be smart to incorporate passive solar principles into the design of your home. Improved comfort and reduced cooling and heating energy bills can be achieved through passive solar design. Builders and designers use solar geometry concepts to integrate passive solar design into a home. Practically any type of architectural style can be employed with PSD - the only requirement is a building site which lends itself to the solar design principle of proper orientation.

At its core, passive solar design consists of the following – minimize solar heat gain in the summer and maximize it in the winter. The strategies used to arrive at this result can vary by region and specific structure location but in general always include…

• Use of sunlight for natural lighting

• Eliminate or reduce cooling requirements through proper ventilation

• Heat storage attained via thermal mass in floors and walls

• Proper sizing of south-facing overhangs of windows to allow for shade in summer and solar gain in winter

• Size and orient windows to achieve more heat gain in winter and less in summer

• General orientation of the house has long axis on east/west plane

• Use of energy efficient materials and products in home construction

The best passive solar design won’t help much if the building envelope is not tight. It’s important to ensure a well-sealed home in order to assist in reducing heat gain and loss. Steps to be taken to achieve this include proper installation of insulation, advanced framing techniques or use of new building envelope products such as structural insulated panels or insulated concrete forms, and tight ducts.

Site orientation is one of if not the most important aspect of passive solar design. In cooler climates a building’s south face should generally be clear of trees and other objects that might block solar gain, whereas in warmer climates you want to be careful not to have too much direct sunlight hitting large sections of south-facing windows and thermal mass walls. Generally speaking, about 90 percent of solar heat gain is realized from external walls that face within 30 degrees of due south.

Window selection is another critical aspect of passive solar design. The challenge here is to avoid overheating by properly sizing south-facing glass, balancing heat loss and gain as needed for your climate. In cooler climates it’s a good idea to reduce window exposure on the east-, west-, and north-facing walls but still allow enough for ample day-lighting. In warmer climates the south-facing windows should be well shaded, especially in summer months. This can be attained through the use of roof overhangs, shutters, wind screens, and landscaping.

Incorporating passive solar principles into your home design can drastically cut your heating and cooling costs and the best part is that it doesn’t really add any cost to the construction of your home other than the design itself.