1. First open enough windows or doors. It is important to let the fan "breathe" in as much air as it needs. Hint: Look at the size of the shutter in the ceiling. This represents the minimum amount of window that should be open.
a. High Speed: If you want to run the fan at the highest speed, you will need to open the windows at least as much as the size of the hole of the shutter in the ceiling. You can open more, but that should be the minimum.
b. Low Speed: Open about 1/2 to 2/3 as much window space as the shutter hole in the ceiling.
c. A 30" whole house attic fan requires at least 6 square feet of window opening to operate properly at high speed, 4 square feet on low. A 36" fan requires 9 square feet of window opening to operate properly at high speed, 6 square feet on low. A 42 inch fan needs 9 square feet of window opening for low and 12 square feet for high speed.
2. Set the speed control on high speed to start. Even if you will be running the attic fan on "low", it will be less stressful on the motor to start on high speed. Set the switch to low after the shutter slats open.
3. Set the timer. If you are using a digital timer, the red light means the timer is energized and ready. Press the lower “time” button for the desired amount of time. Now you should have both the red power light and green time light lit. Then press the upper “on/off” button to start the fan. Both lights turn green and the fan will run for the set period of time. Press any button to shut fan off.
If you have a rotary timer, set the time for at least 2 hours. You can then turn it backward for less timer. Press the start button on the digital timer to begin.
That's it. Other than opening the windows first, there is no "right" or "wrong" way to use the attic fan. Just experiment until you are comfortable and getting the relief you want.
Here is some additional information:
A. A Whole House Fan does 3 things:
(1) Creates a breeze from any opening the fan shutter location.
(2) Flushes the hot air in the breeze path by blowing it into the attic.
(3) Blows out the very hot attic air through the holes (vents) to the outdoors.
B. Wherever you open the windows, you will feel the breeze. Try opening the windows in the rooms you are using, or plan to use.
C. An incoming breeze, even a warm breeze, will feel much more comfortable than no breeze at all.
Tips for using your attic fan
Morning: In the morning, open any window to get a fresh morning breeze. As it warms up outdoors, turn the fan off and close the house up. You would not let cold air into the house in the winter. Keep the hot air out as long as possible.
Afternoon: The house will not heat up instantly. It takes several hours for the heat to penetrate. Usually around noon, the house will begin to feel warm. When that happens, open the basement windows and the door to the basement. Turn on the attic fan and let the cooler basement air flush out the warmer air in your house and attic. When the air feels warm coming from the basement, turn off the fan.
If you do not have a basement or do not want to open the windows there, try opening the windows on the coolest side of the house instead.
If you want even cooler air coming into the house, try this: with a garden hose, water the lawn or wet the area outside the open windows. Open the windows facing the wet area and turn on the attic fan. The air moving over the wet area and through the windows will will feel cooler due to the effect of evaporation.
Evening: The cooler evening air coming through any window will provide comfort. Be sure to open the bedroom windows 1/2 hour before going to bed. The bedroom will be cool and pleasant. You might continue to run the fan after you have gone to bed and by setting the timer, the fan will turn off before you get too cold.
Allergies: Many customers have been apprehensive about installing a whole house fan, thinking that it will increase their allergy suffering. To date, we have not been able to establish whether or not the fans make allergies worse or better. We would welcome reports of any experience you might have had with this issue.
A common sense approach would be to purchase some paper furnace filters and cut them to fit several windows. Try running the whole house fan with the filters in place. They should remove most common allergens. Remember to open more windows in order to make up for the air flow restriction caused by the filters.
Radon/Air Quality: The interiors of homes are usually far more polluted than the outside air. Using the fan will actually reduce indoor pollution and large amounts of air flushing out the basement will help mitigate radon concentrations. The fan may be used year round, even in the winter for short periods of time without significantly affecting heating bills. Flush out the house when painting, using noxious chemicals or when you've burned the toast or roast.