R.E. Williams offers three types of whole house fans, with an estimated air exchange of five minutes for a 1,500-square-foot home and a 10-minute air exchange for homes of 3,000 square feet:

1) The HV1000 whole house fan requires no maintenance and has an R-22 insulated door, which, when not in use, forms an airtight seal between your attic and living space. This basic fan costs $550.

2) The “Ghost” (shown above) is a two-speed whole house fan with a remote on/off switch. This is an easily installed and energy-efficient large-diameter fan that closes and seals when not in use. It comes with a three-year warranty and costs $1,250.

3) The ”Superfan” (shown below) is an energy-efficient whole house fan that does not require any maintenance. It has one central unit with a German-made fan motor known as a backward curved impeller motor, designed to pull large amounts of air through the air ducts quietly. It also has an on/off switch and a wireless remote control option. The Superfan is rated for all homes up to 3,000 square feet, though it is not recommended for homes in very cold climates. Cost is $1,550, with installation estimated at between $400 and $500.