Differences between a Whole House Fan and an Attic Fan
Many people confuse whole house fans with attic fans. This is due to the fact that back in the 1960s when whole house fans were invented, everyone called them attic fans! This confusion is still very prevalent today. Even though they are completely different products, they work together to create the best cooling and ventilation system you can install in your home.
A whole house fan is used for cooling and ventilating both the home and attic. Most people run them during the evening throughout the night and into the early morning, pretty much any time it is cooler outside than inside. This cools, ventilates, and exhausts all the hot, stale air in your home and attic. You would never run your whole house fan during the middle of the day during the summer because it would heat your home. You would only run your whole house fan during the winter months when you're trying to get a quick complete air exchange or heat your home on a warm winter day.
Attic fans cool, ventilate and exhaust your attic only. You use them primarily during the day but they work effectively in the evening and night as well. Attic fans pull air from the outside through existing roof vents in your attic. This allows your attic to stay within 5-10ºF of the outside temperature at all times when the fan is running. Without an attic fan, your attic can get up to 150ºF - 160ºF during the summer, which can ruin the structure of your home and cause high energy bills.
Homeowners often, during the winter months, use an attic fan. In the winter months, mold and moisture can build up because of the air in the home being warm versus the attic air being cold. When it snows on the roof, then it becomes ice and holds excess water. This is known as ice damming, and it will cause mold, mildew, and premature roof rotting. Attic fans help with constant air flow in the attic and lowers the overall humidity level and helps keep the attic healthy.An attic fan and a whole house fan are the perfect tandem to cool, ventilate, and exhaust the entire home, day and night, and year-round.