Exhaust Fan Size for a Kitchen – How to Calculate CFM?

How you can calculate exhaust fan size for a kitchen yourself?

A range hood or kitchen Chimneys are on the rise in the Indian market. Since using these products is a new trend in India, a lot of people are seemed to be confused regarding the capacity of the exhaust fan of their Chimney.

It is vital that you choose a CFM range of your exhaust fan after thorough considerations because low powered Exhaust fan can cause a lot of issues. To help you calculate the CFM for your kitchen exhaust fan here, we have explained a step by step guide for calculating everything you need to know to select the ideal kitchen exhaust fan.

The general rule of thumb for choosing exhaust fan size for a kitchen is that it should move at the minimum of 100CFM of air for each 12” width of your stove. So if the size of your stove is 30”, you’d require an exhaust fan that moves a minimum of 250 CFM of air:

Cooktop 2.5’ x100 = 250 CFM exhausts fan size

Room Size

The size of your kitchen also plays a vital role in calculating the required CFM for your kitchen exhaust fan. You should find out the size of your kitchen in cubic feet when calculating the size of the exhaust fan required, since the larger the kitchen, the more venting power it would require to clean the air while in the small kitchen an exhaust fan with low CFM can also do the work.

exhaust fan size for a kitchen

That is why when you are finding out commercial kitchen hood CFM calculation is it good to find out the size of the kitchen beforehand so that you would not end up with a kitchen chimney with inefficient exhaust fan.

Your range hood should be capable of exchanging the air of the kitchen area for the minimum of 15 times each hour or every 40 minutes. For example, if the width, length, and height of your kitchen is 16’,16’,8’  then it’d have 2,018 cubic feet area.

Here is a simple example of this formula:

16’ length x 16’ wide x 8’ high = 2,048 cubic feet

Now, to find out the fan required for your particular kitchen, multiply the cubic feet of your kitchen space by the number of air exchanges, i.e. 15, then divide the sum by the 60, i.e. the number of minutes in an hour.

For example:

Simply take the cubic feet of your kitchen to say 2,048 cubic feet and then multiply it with the number of air exchanges = 2,048 x 15 = 30,720 cubic feet moved per hour. Now divide this sum by 60/ 60 minutes.

30,720 cubic feet ÷ 60 minutes = 512 CFM then this should be your kitchen hood exhaust duct size.

A simple formula that you can use for calculating the duct size is dividing the cubic feet with 4 minutes. You will get the same outcome like the above-mentioned formula check here what is actual cubic feet per minute.

After finding out the required CFM for your kitchen exhaust fan do not forget to go through our list of best kitchen Chimney in India 2019 to understand What are the Best kitchen chimney brands in India?.

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