Exhaust Fan Size Chart: How to measure exhaust fan size?

In a closed space like a kitchen or bathroom, you would need to have an exhaust fan. The exhaust fan is required to ensure that the air circulation is proper. The exhaust fan also helps you get rid of smell and humidity. One another important factor to take care of is the size of the fan. If the fan is small, it would be useless as it would not remove enough air from the room. In such a case, you need to have an exhaust fan of an adequate size to take care of the needs.

In this section, we have listed a size chart to understand what CFM you would need for a standard size room. Check out the details below.

Exhaust Fans in India

Formula to be used

  • Area of the Room = Length * Width * Height
  • Air Changing Rate (ACH) Rate =X Times/Hour
  • Size of Fan = Area of Room * ACH Rate / 60

We have shared a reference table below, but we also understand that the size of your room may be different from the one mentioned in the table. So, what you can do is that you can plug in your values in the formula and get the estimated CFM of the exhaust fan. You can get the recommended CFM of the exhaust fan from the formula or table below. Remember that the ACH is an important factor for consideration. The humid areas like the kitchen, bathroom and utility room would need a higher ACH. You can alter the value of ACH depending on your needs. For example, if you spend a lot of time in your garage and live in a humid climate, you should consider a higher ACH value.

Type of RoomLength (feet) (L)Width  (feet) (W)Height  (feet) (H)Area (cubic feet) (A)Recommended ACH (Times/Hour) (ACH)Size of Ventilation Fan (CFM) (A*ACH/60)
Living Area15101015005125
Utility Room121010120015300

This table should help you choose the size of the exhaust fan, and using this; you can check the available options for you. Avoid buying anything smaller than the recommended value. Also, the higher the CFM, the noisier the exhaust fan can be. You should also check the same and opt for a noiseless exhaust fan wherever possible.