Removing smoke, grease, and foul air is the exhaust fan’s main task in your home. The exhaust fan size for kitchen spaces is vital for this very reason. But not everyone knows enough about these handy devices to make the right choice. In this ultimate guide to exhaust fan size for the kitchen, you will learn the essential information you need to select the correct one for your home.
When you have the right equipment working for you, your home is more comfortable and has fresh air all the time. To find the perfect exhaust fan for your kitchen situation, continue to read our article.
It provides all the information you need to know about exhaust fans so you can find the correct one for your home. The good thing is you do not have to rely on the salesman to do this once you read this article. You will be able to pick out the perfect exhaust fan and be happy with your purchase.
Table of Contents
- What is CFM
- How Do I Calculate CFM for Kitchen Exhaust Fans
- How Many CFMs Should a Range Hood Have
- How Many CFMs Do I Need for an Exhaust Fan
- Is a Higher CFM Better
- For a Higher CFM Kitchen Exhaust Fan, How High Can I Go
- What’s the Minimum CFM Needed in a Hood
- How do I Increase the CFM on My Exhaust Fan
- Is 400 CFM Enough for a Gas Range
- How Much CFM for a fan is Needed for a 90000 BTU Cooktop
- How Much CFM is Too Much CFM for My Vent Hood
- How Do I Choose the Size For a Kitchen Exhaust Fan
- Installing an Exhaust Fan in My Kitchen: What Do I Need to Know
- What is the Standard Size of the Exhaust Fan
- What Size Commercial Exhaust Fan Would I Need for a 12′ x 12′ Kitchen
- The Difference Between an Exhaust Fan and a Ventilation Fan
- How do Exhaust Fans Help in Ventilating a Kitchen
- Does Building Code Require a Kitchen Exhaust Fan
- Are there any Other Rules for Exhaust Fans in a Kitchen
- What is the Exhaust Fan Size for the Kitchen in Inches
- How Can I Choose the Right Kitchen Exhaust Fan for the Kitchen
- Can Stovetop Exhaust Fans Help in Cooling a Kitchen Room
- How do I Clean a Kitchen Exhaust Fan
- What is the Static Pressure for an Exhaust Fan
- Is Metallic or Plastic Fiber Made Exhaust Fans Better for Kitchen Appliances
- Why Can’t they Produce Quiet Exhaust Fans for Kitchens
- Why is the Kitchen Exhaust Hood Necessary
- How Many CFMs do I Need for the Kitchen
- Is 400 CFM Good for a Range Hood
- Is 300 CFM Enough for a Gas Range
- How much CFM is Needed for a Range Hood
- How do you Measure Exhaust Duct Size
- What Size is a Range Hood Duct
- Duct Size Needed for a 170 CFM Kitchen Exhaust Fan
- Duct Size Needed for a 1200 CFM Kitchen Exhaust Fan
- Is Flexible Ducting a Solution for my Kitchen Exhaust?
- Are all Range Hoods the Same Size
- What Size Range Hood do I Need for a 30-Inch Range
- What is the Code for a Range Hood
What is CFM
The letters CFM stand for cubit feet per minute, which translates into how much air moves in one minute. This rating gets calculated when the fan is at its highest speed. The higher the CFM, the more air moves out of the room.
How Do I Calculate CFM for Kitchen Exhaust Fans
An easy-to-use equation helps you calculate the amount of CFM you need for your kitchen space. You need up to 1.0 CFM per square foot your kitchen size is.
To calculate the CFM for your kitchen, you just use the following equation: CFM = (sq. ft. x room height x ACH)/ 60 (per minute). With numbers the equation would look like this– CFM = (800 x 8 x 7-8) / 60.
How Many CFMs Should a Range Hood Have
Well, this depends on the type of range you own. For example, the gas range hood would be the number of BTUs divided by 100. If you have an 80,000 BTU gas range, the hood would be about 800 CFM.
Electric ranges calculate differently since their output does not include fumes, etc. The size of the range calculates the CFM, and if you have a 30 to 42-inch stove, you would need a 600 CFM hood, and a 60-inch range would require a 1200 CFM hood fan.
The ACH letters mean air changes per hour.
How Many CFMs Do I Need for an Exhaust Fan
The size of the exhaust fan would depend on the size of the kitchen. If your kitchen were 1000 square feet in size, 8 feet high, and had an ACH rating of 7, then you would need a fan with a CFM rating of 1000. The actual rating would be 9.33333, etc., and it is always better to go higher than lower.
Or, if you do not have a great selection of fans in that CFM range, it is okay to put 2-500 CFM fans in your kitchen.
Is a Higher CFM Better
Yes, it is. When you are unsure what exhaust fan size you need, go higher. The higher the CFM, the more air moves out of your room, which means you get any smoke, fumes, and grease out faster when you go higher.
A too-small CFM rating will not clear the kitchen very well, and you may be stuck breathing in those fumes, etc., which would be bad for your health.
For a Higher CFM Kitchen Exhaust Fan, How High Can I Go
The largest CFM made for kitchen exhaust fans reaches 2000, which is good if you do a lot of cooking in those cultural food groups that produce plenty of fat, oil, or grease. The more power you have drawing the oil away, the better it is for your appliances and kitchen.
Use your best judgment and factor in how much you cook, what ingredients you use, and how large your kitchen is to guide you. Stay reasonable as a small kitchen certainly does not need 2000 CFM. You may not find many retailers selling this size of kitchen exhaust fans either.
What’s the Minimum CFM Needed in a Hood
The minimum CFM size would be 0.01 CFM per square foot. This low range is for not heavily used kitchens, are located in reasonably dry locations of the country, and remain relatively clean.
For range hoods, you will need 100 CFMs for every 10,000 BTUS your gas range puts out. Then, 600 CFM should be the lowest for electric ranges.
How do I Increase the CFM on My Exhaust Fan
Unfortunately, this is not possible to do. The CFM rating is constant for each fan and depends on the speed of the fan blades at their highest level, and you cannot change that fan speed.
The only way to push the CFM rating higher is to buy another fan with a higher CFM rating and install it in your kitchen. If you think there is a problem with your current fan, try cleaning the filter, cleaning the blower, and checking to see if obstructions are blocking the airflow.
Is 400 CFM Enough for a Gas Range
Yes, if your gas range only produces 40,000 BTUs or lower. A general rule is to have 100 CFM per 10,000 BTUs on a gas range. If your gas range produces 60,000 BTUs, you need an exhaust fan capable of producing 600 CFM.
How Much CFM for a fan is Needed for a 90000 BTU Cooktop
At this level of BTUs, the minimum CFM you need will be 900. Remember the rule of thumb mentioned above. It is okay to go higher if you want. The more powerful the exhaust fan, the faster and more efficient the room clears smoke, grease, and other cooking elements.
How Much CFM is Too Much CFM for My Vent Hood
There is no maximum limit as it will depend on what you are cooking, the size of your kitchen, and the type of range you are using. Most range hoods only go up to 2000 CFM, so it is impossible to go too high.
An exhaust fan motor rated for 900 CFM will work harder than a motor in an Exhaust fan rated for 1000 CFM. That means that your higher-rated exhaust fan should last longer than the lower rate done.
How Do I Choose the Size For a Kitchen Exhaust Fan
Many factors determine which fan size to select. Those factors include the CFM rating, the size of the room, the noise the fan puts out, the blower-style, and the price.
Installing an Exhaust Fan in My Kitchen: What Do I Need to Know
It depends on the type of exhaust fan you buy. There are two main types, the ducted and the ductless exhaust fans. The former option may have limited placement simply because it requires a path for the ducting pipe.
But if you want to vent the kitchen air to the outside, this is a must design. There’s plenty of work and planning to get everything just right, and the ductless option is a lot simpler.
Because of their design, the old kitchen air gets filtered, removing all the smoke, etc., and the clean air is sent back into your kitchen. As such, you can place it anywhere in the room you want, and all you have to do is set it near or install an outlet.
What is the Standard Size of the Exhaust Fan
Please note these minimum measurements if you are installing a new range hood. The minimum should be 24 inches in size for an electric range, and it should be 27 inches for a gas range.
The maximum size for both types of ranges would be 36 inches. For a kitchen ceiling fan, the standard size would depend on the size of the room. For CFM, the size of the electric range determines the hood size, BTUs for gas ranges, and the square footage for the kitchen.
What Size Commercial Exhaust Fan Would I Need for a 12′ x 12′ Kitchen
A 12 by 12-foot kitchen is only 144 square feet. If you are going commercial fans, you will not need a large fan for that small size. What size exhaust fan would I need for a 12’x12′ kitchen? The measure would be 133 CFM minimum.
The Difference Between an Exhaust Fan and a Ventilation Fan
The main difference between these two fans is that the former model removes air only, and the latter will not only remove air but can bring fresh, clean air into your kitchen.
The exhaust fan is a device that operates only in one direction, while the ventilation fan works in two.
How do Exhaust Fans Help in Ventilating a Kitchen
This type of fan helps ventilate a kitchen by removing the dirty air from the room. If the CFM rating is powerful enough, it does so at a high rate. The fan removes smoke, grease, humidity, and even the odor from the room.
Then if it is a ducted system, that dirty air is then vented to the outside. If it is a ductless model, the polluted air is cleaned through a filter and returned to the kitchen. The latter fan type helps keep the kitchen air fresh and easier to breathe.
Does Building Code Require a Kitchen Exhaust Fan
Simply put, do kitchens need exhaust fans?
Not necessarily. An international residential code talks about air replacement for houses. Still, it is not part of the actual building code, and each state or city providers its own regulation for kitchens.
Therefore, some cities and states may have required exhaust fans in kitchens in their building codes while others have not.
It is still a good idea to have an exhaust fan in your kitchen as it will export toxic fumes, grease, etc., to the outside and keep you and your family safe.
Are there any Other Rules for Exhaust Fans in a Kitchen
It depends on where you live as well. California requires exhaust fans in kitchens, but other states do not. If you put one in your home, then the Federal Department of Energy will need that the fan you install meets the standards created by the following organizations:
- American National Standards Institute (ANSI)
- American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
Those rules include where the make-up air comes from, it must be from inside the house, & that make-up air cannot come from short-circuit hoods that draw air from the outside.
What is the Exhaust Fan Size for the Kitchen in Inches
The size in inches for a range hood depends on the type of range you own. The size ranges between 24 and 36 inches for electric, 27 to 36 inches for gas. Then the amount of CFM your fan uses will determine the duct size.
For example, if your fan has a rating between 0 and 400 CFM, you need a duct size of 4 to 6 inches in diameter. The 900 to 1200 CFM would require 10 to 12 inches duct size, and above 1200 CFM, you would need 12-inch duct piping.
The fan can be just about any size for the kitchen as long as the CFM matches the room and the duct size matches up with the CFM strength.
How Can I Choose the Right Kitchen Exhaust Fan for the Kitchen
The key to this objective is to check the square footage of your kitchen.
The standard measurement is 0.01 to 1.0 CFM per square foot. Then you would need to know the purpose of the fan, whether it is for a gas or electric stove or for the room itself.
Another factor will be the fan’s noise level and whether you want a ducted fan or a ductless one. Finally, design and price will play a prominent role in choosing one. The key is to go larger with CFM and not smaller, even if it costs you a bit more money.
Can Stovetop Exhaust Fans Help in Cooling a Kitchen Room
Of course, this depends on your exhaust fan’s location and power. If you have a fan with a high level of CFMs at the peak of your ceiling where the hot air gathers, then yes, you can cool your kitchen down some.
How do I Clean a Kitchen Exhaust Fan
Grease and other particles will build up over time, so it is essential to clean the exteriors of the exhaust fans you have in your kitchen. If you don’t do this regularly, you run the risk of having a fire at some point in time.
To do a good job cleaning, use baking soda and dish soap, mix them in water, and use an excellent sponge to wipe away that grease. Do not forget to soak the grease filter and get it clean.
What is the Static Pressure for an Exhaust Fan
Of course, this occurs when the fan has to work hard against a resisting force to do its job. In other words, to move the air in its intended direction, the fan has to blow harder than the resistance pressure in its way.
The exhaust fan must use more power but deliver less air if intense resisting pressure. The equation to figure this out is discharge pressure – inlet pressure + velocity pressure = static pressure.
Is Metallic or Plastic Fiber Made Exhaust Fans Better for Kitchen Appliances
Years ago, a clear winner was easy, and metal was better because it was more durable and low-quality plastic products. With technology upgrading the different plastic products, those plastic exhaust fans give the metal ones a run for their money.
In the end, for small kitchens, it would be a toss-up as to which was better. But for larger kitchens, you should go with metal.
Why Can’t they Produce Quiet Exhaust Fans for Kitchens
Part of the reason exhaust fans sound so noisy is that someone installed a smaller duct diameter than they should have. Then manufacturers cannot do anything about the noise the airflow makes as it rushes through the blower and the duct piping.
The noise rating of sones is measured when the fan runs at top speed. If the sound is too high, to make it quieter, all you have to do is lower the fan speed.
Why is the Kitchen Exhaust Hood Necessary
One reason is aesthetics; a good-looking range hood adds an element of style and class to your kitchen. Another reason is that these range hoods help keep your kitchen free from grease, heat, smoke, and other irritants that could interfere with your health or your eyes.
How Many CFMs do I Need for the Kitchen
The amount of CFM you will need for your kitchen will depend on the size of the room, and the larger the kitchen, the higher the CFM rating you will need.
It will also depend on whether your home is in a dry or humid region, how often you use your kitchen, and the type of food you are making.
The drier and cleaner the kitchen, the lower the CFM rating you will need.
Is 400 CFM Good for a Range Hood
In certain circumstances, it is. 400 CFM range hood is suitable for any gas range that produces less than 40,000 BTU, and it is too low even for the smallest electric range where the recommended CFM rating is 600.
But, it is always best to go a little higher in CFM to make sure you have the right coverage. Going up to 900 to 1000 CFM will ensure you have enough airflow to remove the grease.
You can always turn the fan down to a lower speed level if you do not need that much.
Is 300 CFM Enough for a Gas Range
Only if you own a gas range that puts out 30,000 BTUs or less; other than that, this low CFM rating is useless to you when your range produces higher levels of BTUs. This CFM rating is half of the recommended CFM strength, even with electric ranges.
When in doubt, go higher and make sure to go high enough as you cannot add more CFM power to an exhaust fan, but you can always lower the speed and the rating.
How much CFM is Needed for a Range Hood
For the electric ranges, you should have an exhaust CFM rating between 600 and 1200, depending on the size of the electric stove. These ratings will be lower than those for a gas range since the electric range does not produce fumes.
The CFM range for a gas stove is 100 CFM per 1000, and it is best to go a little higher than that. Going 300 or more CFM higher than the guide would be okay. For example, if you have a 50,000 BTU gas range, you should use an exhaust hood rated at 800 CFM.
You will always want more CFM than you need.
How do you Measure Exhaust Duct Size
Your exhaust fan or hood has a rating measurement based on the number of CFMs.
| CFM RATING||MINIMUM SIZE|| SUGGESTED SIZE|
| 0 to 400|| 4 inches|| 6 inches|
| 401 to 600|| 6 inches|| 8 inches|
| 601 to 900|| 7 inches|| 8 to 10 inches|
| 901 to 1200|| 8 inches|| 10 to 12 inches|
| 1200 and above|| 10 inches||12 inches|
What Size is a Range Hood Duct
The chart above will work for range hood duct piping. The key is to watch how long you make the pipe as the right size will be a considerable aid in disposing of the bad air even when the diameter is smaller than it should be.
For example, a range hood rated at 600 CFM with an 8-inch diameter duct pipe needs a 5-foot length to be an ideal size. You can use this length calculator to help you figure out the exact length you need.
Duct Size Needed for a 170 CFM Kitchen Exhaust Fan
The diameter of the duct piping should be no smaller than 4 inches, and it is a good recommendation for better airflow that you use a 6-inch diameter pipe. The chart above will guide you in selecting the duct diameter, and then the length calculator will let you know the best length of that ducting system.
Duct Size Needed for a 1200 CFM Kitchen Exhaust Fan
When you refer to the chart above, you will see that the minimum size for a 1200 CFM rated exhaust fan is 8 inches. But for better exporting the lousy air for your kitchen, you should go to the recommended length of 10 or 12 inches.
The larger size helps the fan expel the dirty air faster, and its motor does not have to work as hard.
Is Flexible Ducting a Solution for my Kitchen Exhaust?
No, and the restriction is laid out in the International Residential Code (2015) Section M1503, and it is for safety reasons that flex pipe is not to be used. This restriction also applies to corrugated duct pipes.
The regulation states that the interior of the pipe has to be smooth. Also, do not use plastic vent piping, as those corner pieces come with 90-degree turns.
Are all Range Hoods the Same Size
Sadly, there is no one size fits all solution for the setup of a range hood exhaust fan. The general rule is to go 6 inches larger with the range good than the size of your range. Some exceptions apply to this rule, but it is a good guideline for the most part.
For a grill, you may want to go 10 inches larger with the hood to make sure you capture all the fumes.
What Size Range Hood do I Need for a 30-Inch Range
If you apply the 6-inch rule, the best range hood for that stove size would be 36 inches. That should give you lots of coverage and make sure nothing escapes.
What is the Code for a Range Hood
The International Residential Code is called a model code, and it is not law, but many states use it to create their building codes for range hoods and exhaust fans. Unfortunately, the country has allowed the states or the cities to develop their building codes for the most part.
That means that you need to check your local building codes to see what you can and cannot do when installing a range hood. Do not forget, older houses are often grandfathered in and do not have to meet current codes.
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John Thompson, Writer and Commentator
Soldier, writer, researcher, consultant, and bon vivant, John Thompson is the author of numerous columns, op-eds, reports, briefs, short stories and books as the “Felicity Files” and “Spirit Over Steel: A Chronology of the Second World War” (version III). Often found hunched over his computer, or in his garden, and now often found doing both. His diverse talent has led him to work in industries and projects such as energy, security and home construction and renovation. To see the entire team at Evolutdesign.com, visit Our Team page.