Vent power is measured in cubic feet per minute (CFM). This determines the velocity that air flows in and out of a space. Certain manufacturer’s CFM ratings can include the certified ratings to HVI 916* Airflow Test Procedure or AHAM HRH-2-2019** Standards.
*Home Ventilation Institute (HVI)
**Association of Home Appliance Manufacturers
Home Ventilation Institute (HVI)
HVI certification is important to understand when ventilation product shopping. If a ventilation product is HVI certified, it signifies that the air flow (CFM rate) and noise level (sones) have had their performance tested as indicated under the rated conditions. Visit www.hvi.org to see if your vent has been HVI certified. This way, you can know how your vent will perform based on your preferred type of installation (duct configuration and some speed settings).
Association of Home Appliance Manufacturers (AHAM) Verification
If a ventilation product has been AHAM Verified then an impartial verification of the manufacturer’s air flow (CFM) and noise level (sones) under a variety installation options has been performed. To know if your vent has been AHAM Verified or not, visit www.aham.org. If it has, you should be able to view the results*.
Choosing the Right CFM
It's adviseable to select an appropriately sized ventilation unit with the right CFM level. If you buy a product with a too-low CFM rating, it may not be able to successfully ventilate the air in your kitchen. If you buy a ventilation system with too high of a CFM rating, it can create negative pressure so you'll have to find an alternative way to replenish the air. Also note that if CFM is too high, air can be removed from places where you may not want it to be removed from.
To figure out the minimum CFM requirements, consider several factors, one of which is preferred cooking techniques. If you often sear, blacken or fry, you may need a higher CFM rating to properly refresh the air. Also, if you usually use 4 or more burners, there's a good chance that you may need a higher CFM rating. If you mostly simmer and sauté, or you typically use only 2 burners, then a lower CFM rating should be sufficient for your needs.
Don't forget that the higher the CFM, the louder the hood will be.