Although they can cost three or four times as much as other fans, whole-house fans provide the combined cooling effects of portable, ceiling and window fans. They do this by drawing hot air from inside the home and exhausting it into the attic. In so doing, they cause air movement across the body and they pull cooler, outside air into the home.
Ideally, a whole-house fan should be located centrally in the home in a hallway ceiling on the top-floor where it can easily pull air in open windows. The fan is mounted in the ceiling and is usually covered on the interior side with automatic louvers that open when the fan is on, and close when it is turned off.
When the space is air conditioned or heated, heat gain or loss can be reduced by covering the fan with an insulating blanket (like those made to wrap water heaters) or by installing an insulated, weatherstripped box around it with a removable or hinged lid. Be sure to remove it before operating the fan.