The whole-home Aprilaire Model 8126A Ventilation Control System keeps your indoor air as fresh as possible, making your family healthier and more comfortable. The Aprilaire Model 8126A Ventilation Control System is a whole-home ventilation system that helps you control the air freshness in every room of your home, expelling stale, stagnant air and replacing it with fresh, clean air. This greatly reduces moisture problems, odors and indoor pollutants, such as radon and VOCs. The Aprilaire Model 8126A Ventilation Control System is installed as part of your central heating and cooling system by a local HVAC professional. The Aprilaire Model 8126A Ventilation Control System Provides Easy-to-Use Air Freshness Control Year-Round. The Aprilaire Ventilation Controller decides when and how long to ventilate based on its continuous monitoring of indoor relative humidity, outdoor temperature and user friendly settings. This makes it energy-efficient.