Controls Kit includes Damp Weather Shutoff, Humidistat, Power Supply Unit and Control Cables. The Controls Kit is required on Series 5 and Series 6 Models and is sold separately. The Thermostat is mounted near an intake vent opposite the side where the powered vent is mounted and is set at approximately 40F, the thermostat turns the unit off when the crawlspace temperature drops below the setting. Normally, when the temperature outside is at 40F, the temperature in the crawlspace is approximately 50F. The thermostat helps protect pipes and save energy by turning the vent off when the temperature is close to freezing. The Damp Weather Humidistat is in the same enclosure as the thermostat and mounted near an intake vent. Powered vents stay on when the humidity is below the setting. The vent shuts off when the outside humidity rises above the setting or if there is a quick rise in humidity, such as when it starts to rain.