Did you know that a whole house or attic fan can help keep your home quite comfortable at a fraction of the cost of central air conditioning? In fact, attic fans are enjoying a revival as consumers attempt to keep their energy costs down.

How does whole-house ventilation translate into whole-house cooling? The first step is to install a large three- or four-bladed fan with a diameter of 20 to 36 inches in the attic floor. You'll also want to make certain that this fan is in a central part of the house.

The fan draws air from outside when a few windows are opened on the first and second floors. Whole house fans installed in a hallway ceiling or attic can move 3,000 to 6,000 cubic feet of air per minute. The cooler outside air is drawn up into the attic where it replaces hot attic air which is then pushed through attic vents. For maximum efficiency, fans can be wired to automatically turn off when your air conditioner is in use.

The amount of air coming through the house depends, of course, on the number of open windows. Opening additional windows allows more air through the house. However, if you keep only a few windows open, air will move faster and create a pleasant breeze-like effect.

When having a whole house fan installed, be sure to ask two important questions, (1) What fan size should be used and (2) What type of exhaust ventilation is needed. It's a good idea to work with a local dealer who will be able to advise you on fan size and exhaust ventilation for your home's dimensions.

Using fans can help you keep cool this summer, especially if the outdoor temperature is under 85 degrees Fahrenheit.

"We've learned to rely on air conditioning both at home at in the office," a RAAR spokesman adds. "We may not have a choice at the office because of all the heat generated by such essentials as computers and the need for a controlled climate. However, for consumers looking to save money on their energy bills at home, a fan may be a pleasant alternative."

But when all else fails, remember that the really hot days can't last forever, and autumn is just around the corner.