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Selecting a System

Size is very important to a QuietCool system. If a QuietCool system is not sized properly, the system will not work effectively.

Sizing Formula

We use a general formula of either 2, 2.5, or 3 CFM, or “Cubic Feet per Minute”, per square foot of living space. 2 CFM would provide a good system, 2.5 CFM would provide a better system, and 3 CFM would provide the best system. To calculate how much CFM you need in your home, simply use this calculator:


Fill in the two fields below to calculate CFM and attic venting needed for your system.

Home Square Footage:

System type:

You will need   CFM and approximately sq. feet of attic venting for your system.
The CFM requirement can be achieved with multiple fans.

Sizing Considerations

There are two other considerations to take into account when sizing a whole house fan system:
Location: If located in a coastal region where the climate is cooler, a good system should work great. If located in a desert region where the climate is very hot during the day, but cooler during the night, a best system would make the most sense.
Ceiling Height: If the ceilings in the home are taller than 8 feet, be sure to size the system a little bit larger to account for the increased air volume inside of the home.

Zoned and Central

After determining the total amount of airflow needed in the system, it is time to select a system. We offer three types of systems:
Superior System: Zoned Cooling with multiple QuietCool Energy Saver or Stealth Pro fans in the system.
Advanced System: Zoned Cooling with multiple QuietCool Classic or Trident Pro fans in the system.
Basic System: Central Cooling with a single QuietCool fan located centrally in the home.
The fans can be from either the Classic or Professional Series.

Central (single-fan) system

A centrally installed system is a single fan system that is installed in a central location in the home, as the name implies. A single system would typically be installed at the midpoint of a single story home, or at the top of the stairs in a two-story home. A single QuietCool system will nicely ventilate an entire home, but lacks the individual room control that a zoned system offers.

Zoned (Multi-fan) system

A multi-fan zoned system gives the homeowner maximum control over their ventilation and cooling needs. When sizing a zoned system, the combined CFM of all zoned units (not each individual fan) needs to add up to the total CFM requirements. All zoned fans can be turned on simultaneously when the entire home needs to be cooled, but a zoned system allows individual bedroom control, for example, and thus zoned systems need to be sized for the zones.