What are thermal curtains?

Thermal curtains are insulated window dressings meant to limit heat loss, or gain, through the traditional thermal weak point of a home's windows. According to HowStuffWorks, thermal curtains are designed to resist the flow of heat into a home on hot days and out of the home on cold days.

According to HowStuffWorks, thermal curtains are generally installed as part of a comprehensive insulation package. They usually consist of a reflective inner layer, a foam-insulated middle, a vapor barrier to stop the flow of moist air across the boundary and a decorative outer layer that makes them look like standard window treatments.