They have thermostats that turn the fan on at a recommended preset temperature of 100 110 degrees.
Blow hot air out of attic.
Newer attic fans have insulated doors that close in 30 seconds when the fan s not operating.
Low cfm similar to a bathroom vent 300cfm and only in the hot spots basically by adding an inline ducting fan to the return ducts for the hotspot rooms.
A ventilator fan can blow conditioned air up or down depending on the position of the blower unit.
This type of vent runs along the entire ridge of your roof.
My idea is to vent the build up of hot air that has risen to the ceiling in the hotspot rooms into the attic so that air from cooler parts of the house can move in.
Trying to solve the heat gain problem in your attic by using a fan is like lying out at the beach with a fan blowing over you and thinking you re not.
This will keep your attic cooler which will reduce the cooling load on your home.
Most homes already have some passive attic venting.
Using a fan to blow hot air out of the attic doesn t address the radiant heat flow from the roof to the attic floor.
On the theme of creating positive pressure in the attic and displacing hot attic air with cooler exterior air ventilation fans designed for foundation ventilation could possibly used in place of 22 5 inch eave vents to push in exterior air and thereby push out attic air through high gable vents and eyebrow vents.
It is placed at the highest point of your roof so that the hot air rises to get out.
However with that understanding that creating negative pressure in the attic can cause all kinds of problems sucking out air from the conditioned space possible back drafting of combustion appliances etc he has come up with the idea to blow air into the attic instead i e creating positive pressure to force the hot air out.
Install electric ventilators and attic fans which remove hot air from an attic.
Attic ventilation fans help cool air your attic by pushing out the stifling hot air from inside the attic and bringing in cool air from outside.
Much of that heat then conducts downward and finds its way into the house.
This prevents hot air from seeping into your home and driving up the temperature in the living space which reduces the load on your air conditioner.
Alternatively install passive vents such as gable soffit and ridge vents which are openings in the roof that allow hot air to escape.
Hot air exhaust vents located at the peak of the roof allow hot air to escape.
There are also room to room ventilator fans to move the conditioned air.
If the temperature outside is cooler than the temperature inside the room face the fan in the window so that it blows air in which can usually be done at night and in the early morning when the air outside is normally cooler.
This sends hot air up and out cooling your house and your attic.
