If you're considering alternative energy sources for your home, you've probably investigated solar panel options and wind energy solutions. But there's another choice available that's reliable, cost-effective and will last a lifetime: passive solar design.

Maybe you've never used the term 'passive solar design', but odds are you've taken advantage of its benefits; for instance, every time you find refuge from the brilliant summer sun under a cool, shaded porch, or open the blinds to garner warmth from that same sun in the winter months. Passive solar energy isn't limited to these handy tricks, but can be incorporated into the entire structure of your home, whether you're building new or retrofitting an existing structure.

In order to make the most of passive solar design, keep a few key factors in mind:

Location
First, is your home in a cool northern, mixed mid-west or a balmy southern setting? The sun travels at different heights depending on your degree of latitude, rising higher overhead as you move southward and producing increasingly warmer temperatures. In the immediate surroundings, local elements like trees, hills and additional buildings can all create cooling shade and act as a buffer against the wind.

The size and shape of your home directly influence the interior temperature. The interior space receives more sun exposure (making it warmer) when the structure of the building is long and narrow, facing south. In contrast, a less rectangular, more compact, home stays cooler with greater interior depth and more space in shadow. The directional placement of a home is key. When the sun moves lower in the winter, it's ideally positioned to shine through windows. It's higher summer transit keeps it from beating against the side walls if the longer sides of your home run along an east-west line.

Materials
Different building materials retain different amounts of heat. Stone, earth and brick are excellent materials for storing heat known as thermal mass. Heat always travels to the cooler areas, and these materials are helpful in keeping your home comfortable year round. Strategically placed thermal mass can markedly improve your home's interior temperature.