Whole House Fans
Using Whole-house roof fans with roof wind turbines
When whole-house fans are used in conjunction with roof wind turbines a temperature drop of 3 to 8 degrees can be achieved within minutes. Wind turbines typically only spin when the wind is blowing or their is sufficient hot air coming from the attic.
The turning from hot air is usually slow. Crank up a whole house fan and the movement of air thru these wind turbines will make them spin like crazy.
This means that the cool outside air is being drawing thru open windows, thru the whole-house fan, thru the attic and back outside. This process flushes all the hot air out of your home and attic in minutes.
The keys to this system is having the whole-house fan centrally located in your home, usually in a hallway and plenty of roof vents.
Alternatives to wind turbines include, dormer vents, gable end vents and ridge vents or any combination. You may discover that may need a lot of these alternative vents to satisfy the whole-house fan.
Choosing a whole-house fan
When you purchase a whole house fan the written instructions state how much free net area of exhaust the fan needs. The net free area is often called out in square feet or square inches. For the greatest convenience, choose one with a built-in timer, for automatic operation.
Some automatically switch from high to low speed after 30 minutes.
Most models offer air sealing shutters to seal off the fan when it is not running.
Motorized insulated shutters are also available.