How Much Energy Does A Whole House Fan Use?

Whole house fans use 200 to 650 Watts of energy in an hour depending on their CFM rating. Likewise, it will cost an average of 2.6 to 9.1 cents an hour to run a whole house fan.

Table of Contents

Here is the list of popular whole house fans and the energy they use;

Model	CFM	Energy consumed	Cost per hour*
Tamarack Technologies HV1000 R38	1000	70 Watts per hour	0.91 cents
QuietCool QC CL-1500	1472	117 Watts per hour	1.521 cents
QuietCool QC CL-2250	2280	250 Watts per hour	3.250 cents
Cool Attic CX24DDWT	2985	150 Watts per hour	1.950 cents
QuietCool QC CL-3100	3126	320 Watts per hour	4.160 cents
QuietCool QC CL-4700	4505	591 Watts per hour	7.683 cents
QuietCool QC CL-5400	5024	649 Watts per hour	8.437 cents
QuietCool QC CL-6000	5665	769 Watts per hour	9.997 cents
QuietCool QC CL-7000	6924	1147 Watts per hour	14.911 cents

List of popular whole house fans and their energy consumption

* The cost per hour is calculated based on the average kilowatt per hour rate across the USA which is 13 cents.

As per the table, the Wattages of whole house fans range from 70 to 1147. However, the most popular choices are between 2000 to 5000 CFM, and so it is safe to assume that the energy consumption of whole house fans ranges from 200 to 650 Watts.

How to reduce the energy consumption of whole house fans?

Whole house fans only use a fraction of the energy used by air conditioning equipment. However, their incorrect use can drive up your energy bills. Here are a few things to make sure that they run energy efficient;

Make sure the attic has proper ventilation

Having proper attic ventilation is very important for the efficient working of whole house fans. A thumb rule is to leave 1 sq.ft of attic ventilation for every 750 CFM of the attic fan. This of course means that the air should be able to flow through the vent without obstructions. The presence of nets and grills will obstruct airflow to some good extent. So in this case the required attic ventilation area is 25 to 50% more than what is mentioned above.

If proper attic ventilation is not provided the whole house fan won’t be able to push the hot air out into the environment. This will reduce the suction of hot air from the house, increase the load on the motor of the fan, and thus increases energy consumption. So for the energy-efficient working of the fan, it is important to leave your attic with enough ventilations.

Open enough windows and doors

Since whole house fans draw air from the outside it is important to keep some windows open during their operation. The suction power of these fans is so huge that they can create a negative pressure in the house. Keeping two or three windows open will make sure that the fan is able to draw in enough fresh air from the outside. Failure to draw air will increase the load on the motor which will lead to more energy consumption and maybe damage the fan.

Install the fan in a central position

Whole house fans should be installed at a location that makes them easy to draw air from all the rooms. The purpose of using a whole house fan is to cool the house by providing a cool airflow. If the fan is located very far from some rooms or in a corner of the house then it will have to work longer to cool the living spaces. This will mean more energy consumption. So to keep energy consumption to the minimum whole house fans should be installed at a central, open location of the house.

A comparison of the energy consumption of common household appliances to a whole house fan

Appliance name	Energy consumption (Watt)
Whole house fan	700
Air conditioner	3500
Ceiling fan	65
Clothes dryer	5000
Coffee maker	900
Vacuum cleaner	800
Water heater	3800
Refrigerator	500
Microwave Oven	1000
Iron	1000
Dishwasher	1500

Comparison of energy consumption of a whole house fan to other electrical appliances

From the above table, you can see that whole-house fans do not consume as much energy as many appliances we use daily at home.

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