These vents help the homeowner out in several different ways. You don’t have to remember to dose your foundation vents in the winter or open them in the summer. Automatic foundation vents give you a tighter seal when closed by louvers overlapping each other. When vents are open this help to cause a cross draft under the home to help keep moisture out. By being thermostatically controlled these vents close all the way at 50 degrees and below. They open all the way at 70 degree and above. I’m between these temperatures the louvers will open a little accordingly.