The Aprilaire Model 8126 Ventilation Control System offers proper ventilation at an affordable price. Only the Aprilaire Ventilation Control System has the automated controls to manage circulation year round and ensure homes get the kind of air they need, when they need it. Installed as part of the home’s heating/cooling system, the controller works in conjunction with an Aprilaire motorized damper to continuously monitor the humidity levels in the home and the outdoor temperature of fresh air entering the home. Combining this information with flexible, user-adjustable controls allows homeowners to manage both the quantity and quality of circulated air being brought into the home.