by Pat Fox

Created on: October 30, 2008

Passive solar is a powerful design element which, if used well, combines beauty and purpose to help manage your home's heating and cooling requirements. A well constructed passive solar design will maximize the use of the sun's energy to light and heat your home while reducing your utility bills.

There are several basic principles that need to be considered when incorporating passive solar into your design. First, plan to leverage the southern exposure. For new construction, position the house so it faces south. Plan for windows on the south side to bring heat and light into the building and design the layout of your home so the primary living spaces are on this side. Rooms that are used less often, such as bathrooms, should be built on the north side of the house.

As you design the south-facing side of the house, consider how to maximize the use of the solar energy in the winter while avoiding overheating in the summer. In the winter the sun's rays are at a low angle, so you need to minimize the shading around your building. In the summer, the sun's rays are at a higher angle. To insure your comfort you will want to design for some shading for your living space. Deciduous trees can be planted on the south side of the house to help with this issue. They will lose their leaves in the fall allowing the sun to shine directly into the home and they will provide much needed shade in the summer.

Another option to consider is the use of overhangs. Planning the roof so it hangs over the south side of the house will provide shade in the summer while not blocking any of the rays in the winter. This technique has been used in homes for centuries. The traditional wrap-around or front porch provides much needed shade to the interior of a home in the summer while providing the added benefit of a wonderful outside sitting space on warm summer evenings.

The next critical consideration is to be sure that the home is well insulated. Using the warmth of the sun's rays will be much less effective if the heat simply escapes through the walls. Work with your contractor to install the appropriate R-value insulation in the walls, floor and ceilings and seek to seal air leaks with expanding foam around any pipes or vents that penetrate the exterior of your building.

The effective use of thermal mass is the next thing to think about in your design. Materials such as tile, concrete, bricks, and rocks will absorb the heat from the sun during the day and radiate it into your home in the evening. This will prolong your enjoyment of the solar heat after the sun goes down and reduce the amount of time an alternative heat source is needed.

Finally it is important to consider how you live in your passive solar home. Enjoy the warm sunny rooms during the day, but be sure to have insulating drapes, blinds or shades that can be drawn at night. This will add beauty to your living space and reduce any heat loss through your windows.

The sun provides a free source of energy. Passive solar design is a great way to take advantage of this resource. Although it requires an initial investment to do it well, the payback both financially and in quality of life is endless.

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