How Many CFM Do I Need for My Range Hood?

There are several things you need to take into consideration when selecting the best possible range hood types, including size, mount, power, noise, heat, and ventilation of the unit, as well as the quality of the filter. The most confusing issue for most customers is the power of the appliance they purchase.

If you are not a machine expert like me, this calculating method may seem a bit mystifying and brain-racking for you at first glance. I understand entirely, but don’t worry! Unlike many others, this rule is precise and straightforward. So, you will solve the range-power hood puzzle without many complications after clarifications and with proper guidance. Let’s see.

What Does CFM Mean?

The first thing you need to know is what precisely the abbreviation CFM means. CFM (cubic feet per minute) represents the unit that measures how fast the air flows into a place or out of it.

Since the higher CFM means the higher air velocity and more air movement, it will affect the air quality in your home and lead to more ventilation and reduction of awful odors in the kitchen. Therefore, it is essential and the most relevant parameter you should think about when you need to decide which appliance to purchase.

Several elements can affect the CFM, such as the power source of your stove, the place where you plan to hang your new range hood, and its purpose in your home.

The Power Source

The Power Source

There are two power sources you can use in your kitchen, including the electrical and gas types. The difference between them is significant, and there are two separate methods to calculate the CFM for your new device.

Check the one relevant to the range hood you want to install in your kitchen. Keep in mind that I will show you the calculation for ordinary conditions in your household. The system is a bit different for the units used in professional kitchens.

Electrical energy source

You should prepare the measuring tape and determine the width of your range top. On average, you will need 100 to 120 CFM for every 10 inches (24.5 cm). Therefore, if your range top is 50 inches (1.3 m) wide, you will need a range hood with at least 500 to 600 CFM.

Gas energy source

In case you cook on gas, you will need to do a different math formula. You will need to use the BTU (British thermal unit) to make the right calculation since gas appliances have the specifications and capacity showed in this particular unit.

Even though BTU is a non-SI, it is a part of the US customary units. It is the unit measuring the capacity of the heat that your gas burner gives off. Basically, one BTU raises the temperature of the 0.12 gallons (4.5 l) water by one degree Fahrenheit.

Keep in mind that you can’t use this unit to determine the heating power of your electric stove. In case you have that one, you need to use watts (1 watt is equal to 3.4 BTUs/h).

Anyway, to get the number of CFM for your gas appliance, you should use the BTU value and divide it with 100. For instance, if you have the gas stove of 65,000 BTU capacity, you should divide it with 100.

As a result, you will get 650 CFM accordingly, which means that you need to buy the range hood that has at least 650 CFM to satisfy your cooking needs.

Variations That Band the Rule

Variations That Band the Rule

Always be aware that many things can affect the proper calculation you want to make. Therefore, you should consider variables you need to add when looking for the right CFM for your new device.

Variations connected to installation and pipes

  • If your piping in the duck system is long, you need to add 1 CFM for each foot (30.5 cm) of piping
  • If you have many pipe angles, you need to add an extra 25 CFM for each angle
  • If you have any roof cap, you need to add another 40 CFM to the calculation

Adding an extra CFM is crucial for the high performance of your new range hood.

Variations connected to the position of your range hood

Among the variations, you should consider, is the position of your range hood, as well.

For example, you may want to purchase a range hood that hangs from the ceiling. In that case, the breeze of your household air will affect the circulation of air going into this range hood. Therefore, you need to add extra CFMs to the calculation for the higher efficiency of your device.

On the other hand, under the cupboard range hood won’t need extra adding since the fumes hit the wall, and the breeze in the kitchen can’t affect it.

One more thing! If your device is placed more than 36 inches (99.5 cm) above the stove, you need to increase the number of CFMs to provide more power for sucking out from the further distance.

Variations connected to the size of the kitchen

Calculating the volume of the cooking area is essential since kitchen air goes through the range hood every 4 minutes. Therefore, you need to determine it by measuring the width, height, and length of your kitchen. Then use an online calculator to do the math.

Professional Range Hood CFM

Unfortunately, the previous rules can’t help you if you need to determine the CFM for professional use. The necessary CFM can’t be less than 900 since you need faster air flows there.

That style of cooking is not possible without ducted ventilation because a ductless range hood won’t be able to purify all amounts of smoke, odor, and fumes produced in the professional kitchen. Furthermore, changing filters every 2 to 3 weeks is too expensive.

Conclusion

Your cooking style, type of range hood, and size of your kitchen will directly define the CFM you need. Take your time, consider all the variations, and use an online calculator to do the correct calculation. Then, the best part comes. You can go shopping!

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