How do I Use Attic Ventilators to Prevent Ice Dams?
Q: "Should I keep attic turbine ventilators spinning in winter?"
We have turbine ventilators on the back side of our house roof to keep the attic cool in the summer. But what should I do with the ventilators in the winter? Some people tell me to close them up, while others say to let them spin.
—Rick Bakies, Seymour, Conn.
Tom Silva replies: Let them spin. An attic needs to exhaust moisture just as much in the winter as it does in the summer. But attic ventilation serves another important purpose in cold weather: It removes heat that escapes from the house. A cold attic means a cold roof, and a cold roof doesn't suffer from ice-damming problems.