How To Test Range Hood Suction: 3 Testing Methods

Have you noticed lately that the kitchen has an unpleasant atmosphere or too much humidity? If yes, there’s a high chance your range hood is not working correctly. The issue is, it is not easy to test whether the range hood is pulling air by merely holding your hand in front of it. However, there are easy ways to test this.

The best way of testing a range hood is by producing smoke and seeing whether it gets pulled into the range hood. If the smoke is pulled instantly, your range hood works fine. You can also test the airflow using an Anemometer or by simply checking if the hood damper is working.

You also might have come across the paper test in which you hold a piece of paper before the running hood and see if it gets sucked in. Unfortunately, that method is faulty because range hoods are not supposed to be vacuums. Their suction levels are relatively less and only designed for airborne particles. Therefore, in this read, we’ll be going through multiple effective ways of testing a range hood. Whether you’re testing an old hood or a repaired one, the following methods will suffice.

1. Smoke Test

A normal smoke test is the best way to get an idea of whether your range hood is working smoothly or not. All you have to do is produce enough smoke to examine how much is the range hood sucking visibly. For this purpose, smoke candles are the ideal choice. However, you can also consider other options that produce smoke, such as boiling water, e-cigarettes, or coal. Close the doors and windows of the kitchen and use any source that produces smoke. Once you’ve made a significant amount of smoke nearby the stove, turn on the range hood to its lowest setting. If the smoke completely disappears within three to five minutes, then your hood is working fine.

Here is a video showing a smoke test on a range hood;

smoke testing a range hood

2. CFM Test

A CFM (Cubic Feet per Minute) test will require you to check the CFM of your kitchen’s range hood. The CFM level tells how many cubic feet of air can the range hood suck at its best. Simply put, it is used to measure the effectiveness of a range hood mainly by examining its suction capabilities. Depending upon the frequency and volume of your cooking, your required CFM can be determined by making some calculations. For instance, the needed CFM is 100 for every 10,000 BTUs of the stove.  

There’s no telling how much an average CFM should be since it varies from kitchen to kitchen. To check how much CFM your range hood is giving, we suggest using an anemometer. All you have to do is set the tool on airflow mode and turn the range hood on while the tool is held in front of the hood’s motor fan. Once the anemometer catches the precise CFM measurement through airflow, you can match it with the required CFM rating and see whether it’s acceptable for the hood or not.

Here is a link to an Anemometer (Amazon) if you need one.

3. Damper Test

Range hoods are vented outside and come with a motorized damper that automatically opens itself whenever the hood operates. Once the operation ends, the damper closes its shutters. This prevents the entrance of insects from the outdoors and ensures that the sucked polluted air is escorted outside. However, the dirty air might not completely make its way to the end of the vent if the motorized damper is not working properly. A compromised air seal can lead to polluted air returning to the kitchen and be the reason behind faulty range hood performance.

To see whether the damper is doing its job, simply peek behind the hood’s fan after turning it off and see if the damper retracts or not. If it retracts, then the issue lies elsewhere, but if it doesn’t, then this might be the key reason behind your range hood’s decreased efficiency. 

How to improve range hood suction

The compromised suction of a range hood can be due to multiple reasons. The most common cause of a range hood’s decreased efficiency is the lack of proper maintenance. You can improve your range hood’s suction by giving it a thorough cleaning session. To ensure you achieve the maximum CFM out of the machine, the following methods can be of help:

Clean filters

Cleaning your range hood’s filters is essential for optimal performance. Depending upon which type of filters you use, give them their due maintenance and clean/change them when needed.

Here is a detailed article on cleaning range hood filters.

Clear the duct

If your hood has been around for a while, there’s a chance that debris might have made its way into the duct. Clear it out with the help of a vacuum or a blower. Consider placing a grill on the vent to prevent minor obstacles from sweeping in.

Clean the fan

The fan is the key component of the range hood. If the fan is faulty, the range hood won’t be able to get rid of smoke from your kitchen effectively. Take the fan out and wipe its blades so that it cuts air properly. Also, see if the motor works correctly and does not need repair.

The above-mentioned methods will greatly help in boosting the effectiveness of the range hood. If these don’t work, you should consider having a professional over to take a look.


It can be difficult to tell whether a range hood is performing at its best or not. However, it is always recommended to give them their timely maintenance. Lastly, another possible reason could be the range hood not being powerful enough to tackle your daily life cooking adventures. In such a case, it would be best to have it replaced with a better one that suits your needs.

Charles John

Experienced HVAC technician with 8 years of experience in the industry. Capable of handling all sorts of heating and cooling equipment as well as proficient in operational management, construction-related techniques such as preventative maintenance, electrical troubleshooting and AutoCAD

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