When buying drapes for your windows, consider more than just fabric, color and style: Think thermal. Thermal drapes are lined to help block heat, harmful UV rays and drafts. They are also useful in the hot summer months -- they can block the rays from the sun that heat up your home. Just by switching to thermal drapes, you can save as much as 20 percent on your energy bill. On average, that equals about $480 a year for a typical household. Over time, your drapes could actually pay for themselves.