An attic fan. (D. Friedman / June 2, 2014)

To lower the use and expense of air conditioning a home in the dog days of summer, consider installing an attic fan to cool down the house. An attic or whole house fan is designed to work best in the evening when temperatures are the coolest. When you open windows and turn on the fan, it draws in cool, fresh air and forces it out through attic vents. By morning you'll be reaching for a blanket.

An electrician charges $568 to install a direct-drive attic fan that cools a typical 1,500 square foot house. This includes labor and material. A homeowner with electrical and carpentry skills can buy one for $195 and install it, saving 65 percent. The project involves some major work: cutting an opening in the ceiling, installing the unit in the opening, hooking up the wires and then adding the louvered cover panel.

Follow the fan manufacturer's directions about wiring the unit into your home's electrical system and to any switches or controls you choose. For the easiest installation, choose a direct-drive unit that's designed to fit over the attic floor joists so you don't have to cut into them. You'll find them at home centers and lumberyards.

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Pro Cost -- DIY Cost -- Pro time -- DIY Time -- DIY Savings -- Percent Saved

$568 -- $195 -- 5.6 -- 10.0 -- $373 -- 66 Percent