Fans

Can I save money by using my ceiling fans during summer months?
Ceiling fans make you more comfortable by creating a “wind chill” effect that can make you feel up to five degrees cooler. However, unless you set your thermostat temperature higher, fans will not save you money. You should turn off fans when you leave the room. Ceiling fans do not reduce the temperature in the room. They merely circulate air, making you feel cooler.

I have vaulted ceilings and ceiling fans. I'm sure my attic space gets well over 130-140 degrees. Would a powered attic ventilator help keep my house cooler and reduce my air conditioning load? The unit I am considering has a thermostat to turn on and off. There is R-30 to R38 insulation over the living space.
Building scientists agree that powered attic fans are not recommended in Arizona. They use more power than they save. Fans draw air from the house through numerous small cracks and utility penetrations in the ceiling and walls. That air has to be replaced with outside air that has to be cooled, increasing the cost.

A properly vented attic shouldn't be more than 10-15 degrees hotter than the outside temperature. If it is more than that, check the vents and the path between vents to make sure they are clear to ensure proper air flow through the attic. 

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