Forget shopping around for the lowest-price heating fuels or more efficient air conditioners – the best way to save on heating and cooling is to pay more attention to how passive energy from the sun affects your home. This practice, known as passive solar design, allows you to take full advantage of free heat from the sun in cold climates while minimizing unwanted solar heat gain in hotter climate zones.  You can't redesign your home once it's built, but the proper use of window treatments, like those from Landis Decorating Inc, can help you cut energy costs and make your home more comfortable and efficient.

Heat from the sun's rays enters the home through walls, windows, doors, and the roof. In hot climate zones like the Southwest, as much as 20 percent of solar heat gain can be attributed to sunlight passing through windows. Using the right window coverings to block this sunlight can help keep your home cool and reduce air conditioning use.  

To get the most bang for your buck, focus on south, east and west-facing windows. The treatments you use on north-facing windows don't matter as much, because little sunlight enters from the north. You may wish to add treatments to north-facing windows for aesthetics, or to control lighting.

The best way to keep sun out is to use a reflective film on the inside of windows. Exterior shades or screens made from aluminum, fiberglass or vinyl can also be placed over these windows during the day to keep solar heat out of the home. Finally, consider regular interior draperies and curtains. The U.S. Department of Energy estimates that simple medium-colored drapes with a reflective backing reduce unwanted heat gain by as much as one-third.

Of course, you'll want to take an opposing strategy if you live in a colder climate zone, like the Northeast. In colder areas, keep east, west and south-facing windows free of any treatments during the day as a way to maximize solar heat gain into the home. Once the sun sets, close drapes or other window treatments to keep heat from escaping back out through the windows.

The DOE estimates that even using regular drapes can cut heat loss at night by 10 percent, which can mean a big difference in your heating bill. If you install drapes so they touch the ceiling and use Velcro or magnets to keep the edges sealed to the wall, you can cut heat loss through windows by 25 percent.