whole-house fan basics

Whole house fans can lower indoor temperatures by several degrees in just a few minutes... if outside temperatures are cool enough. Whole-house fans can be extremely effective as cooling devices in hot climates and hot weather conditions.

Whole house fans are used to pull cooler outside air through open windows and to exhaust hot indoor air through the attic vents and roof vents.

Larger whole-house fans may provide 30 to 60 air changes per hour in a typical home, though 10 air changes or something around that is sufficient in most cases.

Difference between an attic fan and a whole house fan

Traditional Whole House Fan Whole house fans are often confused with attic fans, but they are very different devices.

An attic fan (eventually a solar attic fan) is usually installed in the roof in order to remove hot air from the attic (and only the attic).

Whole house fans are usually installed in the attic but have a much wider goal than attic fans: cooling the whole home and not just the attic.

Do not also confuse whole-house fans with evaporative (swamp) coolers.

Energy savings

A whole-house fan demands around one-tenth of the power of an air-conditioning system, allowing huge energy savings.

Open the windows

The use of a whole-house fan depends on open windows and good airflow (and outside fresh air). Otherwise, the device will not function properly, and you may damage it.

Opening your windows is also important to prevent the whole-house fan to driven fumes, gases or flames from your domestic appliances into your living space – something you may want to discuss with the contractor.

Closed windows

Obviously, you may close windows in unused rooms, as long as other windows remain open. Keeping some windows close, will create more air movement in other rooms…

Whole House Fans Limitations

Whole house fans have obvious limitations, mainly because their use is largely dependent on specif outdoor weather conditions.

See: Advantages and Drawbacks of Whole House Fans

An Alternative to air conditioning

Whole house fans can replace air conditioners in hot and temperate climates (in normal humidity conditions). They are typically used in the early morning or late evening and night, when the outside temperatures are fresher and cooler than those of inside air.

Alone or associated with ceiling fans and other circulating fans, they can provide cheap cooling comfort.

According to EERE, the replacement of classic air conditioning by whole-house fans can lower cooling costs by around 30 percent in many US climates.

Air conditioners

Do not operate air conditioning and whole house-fans simultaneously. Whole-house fans demand the opening of the windows, which collides with air conditioning functioning. Turn the air conditioning off, when using the whole-house fan.

Whole House Fans Location

As a rule whole house fans are located on the highest ceiling of the house and oriented to an attic space.

See, for more details: Sizing and Installing Whole House Fans

Cost

Whole-house fans are cheap devices. Prices between $300 and $600 are common for traditional models, but there are other more expensive models.

See, for more details: Prices and Manufacturers of Whole House Fans and Tips on Sel ecting a Whole House Fan.