A home with solar panels is already more energy efficient than it once was, and utilizing passive solar home design can make such a home even more efficient and pass cost-cutting onto the homeowners.
Passive solar home design takes into account a home’s building site, climate, and materials in order to reduce energy use. The most effective way to lower energy use is to lower the need for it. Passive solar home design creates a smaller need for heating and cooling and then utilizes solar energy to provide that heating and cooling.
An energy efficient system is the most effective means to cutting down on heating and cooling costs. If you don’t need to turn on the heat or air conditioning as often, you won’t need to pay for the energy to run them. Passive solar design is built on this concept, so it’s important for homeowners to build with efficiency in mind. Choose a site location that is hospitable to solar energy, and hire professionals with experience in energy efficient house design.
If you are building a new passive solar home, part of the south side of the house must be unobstructed from the sun. Keep this in mind if your new home currently has an unobstructed view of the sun, as it might not in a few years if you plant small trees in that part of the site.
How Passive Solar Design Works
Basically, the home is built to trap heat from the sun striking the south side and to retain that heat in building materials. The partnership of solar heating and stored energy from the passive design work together to cut energy costs and provide a comfortable home year round.
Your windows should be oriented to face within 30 degrees of true south and should not be shaded by other buildings or trees from 9 a.m. to 3 p.m. each day. In the winter, windows should be shaded to avoid overheating. Thermal mass (concrete, brick, etc.) stores sunlight in the warm seasons and absorbs and stores warm air from inside the home during the cool seasons.
Other things to consider during the design of your passive solar home include proper insulation, window location and shading, thermal mass location and type, and auxiliary heating and cooling systems.
Direct and Indirect Gain
In a direct gain design, sunlight enters the house through south-facing windows and is absorbed by masonry floors and/or walls, which store the solar heat. As rooms cool during the night, the thermal mass releases stored heat into the house.
An indirect gain passive solar home houses its thermal storage between the south-facing windows and the rest of the home. The most common approach to indirect gain is a Trombe wall. Think of a Trombe wall like a solar panel; it consists of an 8-inch to 16-inch thick masonry wall on the south side of the house. A single or double layer of glass mounted about one inch or less in front of the wall absorbs solar heat, which is stored in the wall’s mass. The heat migrates through the wall and radiates into the living space.
You may have noticed how little was discussed about heating and cooling systems or maintenance, which is the entire point of the passive solar design. Build your home with the right design, and you can put your feet up while comfortable heat and lower costs find their way to you.