If your kitchen is 12′ x 15′ and 10′ high, that equals 1,800 cubic feet.

To find the size of fan needed, multiply the cubic feet x the # of air exchanges (15) then divide by 60 (minutes in an hour).

In our example that would be: 1,800 x 15 = 27,000 divided by 60 = 450.

You need 450 CFM minimum for this size of kitchen.

## How many CFM for a range hood do I really need?

If the range hood is attached to a wall, you should have 100 cubic feet per minute(cfm) per linear foot. So if you have a 30″ wide range, you should have a hood rated at 250 cfm ((30/12)*100 =250). If the hood is over an island, you’ll use 150 cfm/linear foot.

## How do you size a kitchen exhaust fan?

To find the fan needed for your size kitchen, multiply the number of cubic feet in the room by the number of air exchanges (15), then divide by the number of minutes in an hour (60).

## Is 400 CFM range hood enough?

The Home Ventilating Institute recommends a minimum of 40 cfm for every linear foot of your range. That means a 120-cfm unit should be just enough for an average-size range. Figure up to 400 cfm for a wall unit and as high as 600 cfm for an island cooktop.

Photo in the article by “Wikipedia” `https://en.wikipedia.org/wiki/Cyclonic_separation`