Reduce both moisture and excess heat in your attic with Ventamatic's dual thermostat-humidistat control to avoid mold and mildew issues, prolong the life of your roofing components, and reduce your energy costs when paired with your electric attic fan. This controller mounts to a rafter using wood screws and has a wiring diagram provided to complete installation. As a general rule for power attic vents, your normal temperature setting will range from 95 - 115 degrees F and humidity setting from 60 - 70% depending on average regional temperatures and local humidity levels - a setting too low will run the fan continuously, and a setting too high will result in inadequate ventilation.