Your attic fan may not be turning on because of an electrical problem like a tripped circuit breaker a blown fuse or a bad connection.
How to tell if my attic fan is on.
Likewise adjustable thermostats will shut the fan off.
Good insulation reduces fan effectiveness.
Now take that number and divide it by 750.
Or look at the weather for 2 days with the same weather and monitor temps with and without the fan on each day.
So if your fan is rated at 1500 cfm you will need about two feet of totally open space in your attic.
Attic ventilation fans whether hard wired or powered by their own solar panels seem like a low cost and effective way to help keep your house cool.
This is done because you need one square foot of ventilation area for every 750 cfm that your fan can push.
The downside of attic ventilation fans.
However the utility of attic ventilation fans is actually quite a controversial topic.
Turn the attic fan off and unplug the motor from the thermostat.
If the fan turns on the motor is still good.
How to tell if you need an attic or whole house fan.
The warm air escapes through the attic and to the attic vents allowing the circulation of chilly air from the windows.
Turn your fan off and monitor the temperature in your attic up unitl 2pm or something then turn it on.
If you re running an air conditioner you wouldn t want to have a whole house fan blowing that cooled air into your attic.
You can diagnose it by plugging other electrical appliances that are working into the same outlet and by plugging the fan into a different power outlet.
Once done test that the motor still works by plugging the motor into an extension cord that is connected to an outlet.
Step 1 test the fan motor.
Any whole house fan that you buy should have this figure listed somewhere on the packaging.
You simply add up the nfas of all your vents and divide that number by the area of the attic to determine whether you re within the 1 150 ratio.
Step 2 test the thermostat.
It helps to cool your home temperatures and the attic by approximately 30 degrees.