A range hood blower’s ability to move the air is measured in cubic feet per minute or CFM. The CFM listed for a hood indicates the maximum power available at full speed. To determine what CFM you will need for your range hood, you need to consider a few things.
An electric cook top needs 100 CFM for every 10″ of width. Therefore, a 30″ cooktop would need at least 300 CFM.
For a gas cook top, divide the maximum BTU’s by 100. For example, a 50,000 BTU gas cooktop divided by 100, means you will need a range hood with 500 CFM.
Now, these are the minimum recommendations based on the size of your cook top, but some people will need a Professional Type Range Hood, which means 900 CFM or more. This type of Range Hood needs to be vented outside of your kitchen since it has to move large amounts of air. It would be very costly replacing filters and not as efficient attempting to use this powerful of a blower using a recirculating system.
Reasons for using a Professional Range Hood would include the style of cooking you prefer such as frying, grilling, cooking fishy, spicy or pungent smelling foods. Cooktops with a high BTU, (High heat output) ducting over 100 ft. or multiple 90-degree bends would also be included. If you mount your hood outdoors or are mounting your indoor hood higher than 36 inches above your range top then you need to consider using a larger Professional Range Hood.
Noise Level or Sone Rating
Decide how quiet you want your Range Hood to be. Noise levels are measured in Sones. The lower the sone value, the quieter the hood. One Sone is about the noise level of a quiet refrigerator. The majority of the noise will come from your blower, but air moving past the filters will also create sound. Where the blower is installed can make a difference.
Blowers installed directly inside your Range Hood, also called local blowers can be quiet, but you can lower the noise level by installing a remote blower either in your duct work or on the rooftop. Look for range hoods that have a quiet operating feature to provide you with a better overall experience.
Grease Filters for Range Hoods
Generally, there are two types of grease filters; either baffle or mesh. Mesh filters trap the grease and need to be cleaned frequently. This is so the filters do not restrict the airflow and keep the noise level down. Baffle filters catch the grease and trap it in the filter assembly or a greased tray that can then be removed. Both filters are easy to clean and dishwasher safe.
Looking for more helpful guides on choosing a range hood? Read our other indoor range hood guide to learn about range hood types and venting your hood.