Automatic Temp-Vent is a revolutionary type of foundation ventilator for the crawl space under a home - it opens and closes by itself. Temp-Vents help prevent excess dampness under your home. Temp-Vents help protect and preserve the wood in your home by control of crawlspace dampness. Temp-Vents help prevent pipe freeze-up and helps stop wasted energy and heat loss due to open manual vents. You do nothing after installation. Temp-Vents open and close on their own according to the outside temperature to prevent dampness and to save energy. No motors or electricity. Easily installed. Old fashioned manual vents would require your attention all through the year to save maximum fuel and deter damp rot. Temp-Vents do the job better than manual vents.