The evening air is often quite cool. An investment in a whole-house fan can offer a much better return than even the stock market today.
Most models are sized to fit standard attic floor joist spacing, so they are a breeze to install.
There is even a new quiet mini-model that is sized to cool just one bedroom. Whereas typical central air conditioners can cost about 20 cents per hour to operate, not including maintenance, whole-house fans run for about three to five cents per hour. In fall and spring, a whole-house fan can provide comfortable cooling in almost every climate. To determine if a whole-house fan is right for your home in the summer, check on the typical outdoor nighttime low temperature. If it is about five to ten degrees cooler than your thermostat setting, one will be effective.