The purpose of a solar attic fan is to reduce temperatures inside the attic and other rooms resulting in a cooler, more comfortable home. You will save on your A/C bill and energy use during the long, hot summers in Texas. And during the winter, a solar attic fan helps to prevent moist air from condensing on the under side of the roof, beams and rafters. This, in a sense, humidity control reduces the chance of mold forming and will hinder the deterioration of building materials in your home.