An attic fan is exactly that - it's a fan installed on the ceiling or in the wall of your attic. It works by pushing the hot, humid air out of your attic, and pulls fresh air in, cooling your attic and in turn, cools the rest of your home. This much-needed ventilation is a powerful addition to your HVAC system. Did you know that during the hot summer months, attic temperatures can exceed 160 degrees? Imagine the impact that has on the temperature of your home.