We needed a whole house humidifier but our specific requirements were perhaps unusual. We heat our house by forced air furnace and we have a fireplace that helps with heating bill. We also have large windows facing south so even during very cold weather the furnace gets very little work when sunny. That meant very little humidity introduced into our house if only provided when furnace was active. We designed the humidifier to turn furnace fan on when increased humidity is called for. Plus the furnace on for heat also adds moisture via humidifier. Our Relative Humidity is perfect thanks to Rene’s!