You Should Be Aware Of These 5 Important Facts When Considering A Whole House Fan
When purchasing a whole house fan, there are a number of issues to consider beyond how much air it moves, how it installs, and how much power it consumes.
Alert #1: IF YOU LIVE IN AN AREA WITH A COLD CLIMATE – YOU MUST SEAL YOUR WHOLE HOUSE FAN DURING WINTER MONTHS – OR DUCT THE EXHAUST DIRECTLY OUTSIDE – SERIOUS DAMAGE TO THE HOUSE CAN RESULT!
By design a whole house fan is mounted between the ceiling and attic of your home. When the fan is not running, the hole that air moves through must be closed. Or, the air will continue to move from the house to the attic. It is like leaving a window open. In a cold climate, during the winter months – warm humid air from the house will flow into the attic. The moisture in the air will condense on the cold surfaces (just as it does on cold window surfaces), and water will drip on the insulation and mold will grow. Cover It, Seal It – Or Duct The Exhaust Directly Outside to prevent damaging your home.
Alert #2: USING A WHOLE HOUSE FAN WITH A AUTOMATIC THERMOSTAT IS NOT RECOMMENDED.
Whole house fans can cause back drafting. This condition can occur when all windows, doors and openings of the home are closed – yet, the whole house fan is operating.
Running a whole house fan with windows and doors closed can cause air to flow into the home through vented appliances (Like a gas fired water heater or even a chimney).
If you install your whole house fan to automatically turn on/off based on temperature (installed with a thermostat) and you are not home and your house is sealed, this is not good. That is why we do not recommend running whole house fans with a thermostat, yet we see other vendors selling them alongside whole house fans.
Alert #3: AIR FLOWING INTO THE HOME MUST BE ALLOWED TO FLOW OUT! PROPER ATTENTION MUST BE GIVEN TO THE PRESSURE RELIEF SPECIFICATIONS.
Air blown into the attic must be allowed to escape from the attic to the outside. Otherwise the air will seek other outlets like flowing back down the walls of the house and in through outlets and light fixtures. If you do not have the required net free area of roof venting, you will not only be pumping heat back into your home but the dusty, smelly attic air as well.
Divide the fan’s flow by 750 to determine the necessary, clear opening to the outside. (Insect screens are particularly restrictive to air flow.) For example, a 3000 cfm fan would require in roof venting the equivalent of a 4 square feet to the outside. If the hole is covered by an insect screen, the hole would need to be twice that size.
Alert #4: BE PREPARED TO SIGNIFICANTLY REDUCE YOUR UTILITY BILLS
Using a whole house fan in place of air conditioning will significantly reduce your utility bill.
A whole house fan draws anywhere from 200 – 800 watts of power – about 10 – 15% of the power drawn from a central air conditioner. This is a significant reduction of energy consumption.
Alert #5: PROTECT YOURSELF FROM INSTALLERS WHO MAY OVERCHARGE YOUR FOR INSTALLATION
We recommend getting at least 3 different quotes or bids for your whole house fan installation. You should check each installers license (if applicable), as well as make sure they have liability insurance and worker’s comp insurance. It is also a good idea to check references.
Over the years, we have heard from a few customers who were significantly overcharged for their whole house fan installation. You could expect to pay anywhere from $150-$450 for a fan installation. There are many variables that will determine the exact cost that will be dependent on the setup of your home.