How a Whole House Fan Works

A thermometer against a blue sky with sun in background.

A whole house fan is an electrical device that is installed in the ceiling, between the attic and the living space. Whole house fans provide fast, quiet cooling for the entire home, while effectively reducing air conditioner use. Using a whole house fan is beneficial for the environment, as it reduces greenhouse emissions from air conditioners. It is also considerably cheaper to operate than an air conditioning unit.

Determining the Suitability of a Whole House Fan for Your Home

To maximize the usefulness and energy efficiency of a whole house fan, confirm with the salesperson that the model you buy can efficiently cool your house. Also, measure the center-to-center distance between your attic joists to reduce the time and effort required for installation.

Placing a Whole House Fan

A whole house fan works best when installed in a central location in the house. A hallway is a better option than a room. A wooden frame is constructed as per the dimensions of the whole house fan. The frame is vital because it carries the weight of the fan and allows air to circulate around the fan.

The frame is placed inside the opening at the chosen spot. From here, the whole house fan is installed and connected to the electrical wiring in the house. All openings and cracks must be thoroughly sealed during the process of installation.

Starting the Whole House Fan

When the whole house fan is switched on, it draws any hot air in the house toward the attic, where it is let out through vents. The absence of hot air in the house leads to low pressure. As a result, air from outside the house is drawn in, replacing the hot air that was drawn out through the attic. The whole house fan must have ample ventilation space in the attic. Inadequate ventilation could harm the motor and shorten the lifespan of the fan.

A whole house fan will be ineffective if you close all the doors and windows in your home as you operate the fan. This is because cool air from outside will not have an opening to enter the house.

A whole house fan is only useful when the outside temperature is cooler than that inside the home. If you operate an air conditioner and a whole house fan at the same time you will defeat the purpose of both appliances. The cool air produced by the air conditioner will be drawn outside the house through the attic. In many cases, though, using a whole house fan significantly reduces the need for an air conditioning system or totally eliminates it.

Installing weatherstrips on a window.No A/C? Here are some weatherproofing options for people without air conditioning.