The most important tool in maximizing the efficiency of your kitchen hood is the CFM (Cubic Feet per Minute) calculation. If you have trouble choosing which range hood or island range hood to buy, this guide will make it easier for you to determine how much power you need.
What Is CFM for Kitchen Range Hood?
CFM stands for Cubic Feet per Minute. Simply put, it is the amount of air that your kitchen hood extracts from the kitchen every minute. This is important because this will determine how much smoke, grease, and odors are being pulled out of the space. Other specifications needed to choose an appropriate range hood include noise level, height/depth, light source, number of speeds, and control type.
Since the amount of smoke pulled out of the kitchen can vary according to cooking time or length of usage. Most manufacturers provide a CFM rating for their range hoods under normal conditions. So if you are just cooking up some steak on high heat for 10 minutes, expect a lot of smoke to be produced.
On the other hand, if you are simmering some sauce on low heat for an hour or more, expect less smoke to be produced. Therefore it is best to ensure that your kitchen hood has a higher CFM rating than needed.
What Is a Good CFM for a Range Hood?
A good rule of thumb is around 300 CFM per burner on a gas stove and 600+ CFM for an electric range. However, the proper range hood should be at least 10 times more potent than your cooking equipment. You can check some of the efficient ductless range hood discussions for your home and apartment here in our other review blog.
For example, if you have a 30-inch high gas stove that uses up to 15,000 BTUs, the proper CFM rating is at least 150,000.
CFM Calculation – The Formula
CFM = Kitchen Area (ft.) x Ceiling Height (ft.) x Multiplier of 20 for residences, 10 for commercial buildings.
Calculate Your Kitchen Area
The kitchen area is the total coverage of the room from wall to wall and from floor to ceiling. You can calculate the width and length of your kitchen area by multiplying the width and height of each wall.
Calculate Your Ceiling Height
Ceiling height is the total headroom from floor to ceiling. To calculate your ceiling height, measure from the floor to ceiling and double that number to get your total height (in feet). If you do not have a solid ceiling or beams, you can measure from the floor to any mid-point between beams. The total headroom from the floor to the nearest beam should be used as your ceiling height.
Multiply the result of your Kitchen Area x Ceiling Height by a multiplier of 10 for commercial and 20 for residential. This will give you the required CFM rating that your kitchen hood should have.
CFM Calculator for Range Hood
Kitchen Area (ft.) x Ceiling Height (ft.) = Total area covered by the kitchen hood
CFM required for range hood = Total area covered by the kitchen hood x Multiplier of 10/20 = Required CFM Range Hood
Example: Kitchen Area is 15 ft. x 12 ft. and Ceiling Height is 9 ft.
15ft. x 12 ft. = 180 sq. ft.
180 sq. ft x 9ft ceiling height = 1560 ft/min required to support the range hood.
CFM Range Hood Required = 1560 ft/min x Multiplier of 10 = 16,600 CFM required.
CFM Calculator for Exhaust Fan
If you want to calculate the CFM of your exhaust fan instead, use the same equation but use the sq. ft. of the kitchen area in place of ceiling height. An exhaust fan does not need a high CFM rating since it is usually located close to the cooking equipment.
CFM Calculator for Industry Standards
Generally, a commercial kitchen requires 25 CFM per square foot of kitchen space and a residential kitchen requires 15 to 20 cubic feet of air extraction per minute.
For example, a typical restaurant may require an exhaust fan with a capacity of up to 12,000 cubic feet per minute (cfm) or more.
Rating of CFM for Kitchen Hood
Ensure that your range hood filters have a higher CFM than the hood itself.
Residential Kitchen Range Hoods:
High End – 450 to 550+ CFM.
Mid Range – 300 to 400 CFM.
Entry Level – 200 to 300 CFM.
Commercial Kitchen Range Hoods:
High End – 800 to 2,000+ CFM
Mid Range – 400 to 800 CFM.
Entry Level – 300 to 600 CFM.
Noise level vs CFM of Range hood:
We recommend you to choose a Higher CFM and lower Sones (a unit of perceived loudness equal to the loudness of a 1000-hertz tone at 40 dB above threshold) unit. That means you need to choose an efficient CFM ranged hood while it is produced lower noise so that you can talk while cooking and your range hood is ON.
A normal conversation is 60dB. As such, you need to choose approx 50 to 60 dB (4 to 6 Sones Rating) of Range hood.
Choosing the right CFM rating for your kitchen hood is essential. It determines how much air will be drawn out of your kitchen to keep it cool and clean. However, you also need to consider the other factors along with the noise level produced by the range hood when purchasing one. So do not just focus on CFM ratings but strike a good balance between performance and decibel levels.