How do you calculate the exhaust capacity of your range hood?
What is extraction capacity?
The extraction capacity is the maximum capacity of your range hood. It's expressed in cubic meters per hour. The capacity is the amount and speed to which the range hood extracts air from your kitchen. This may vary for each brand and model. There are range hoods with a capacity of only 160m³, but also powerhouses with an extraction capacity of 800m³ or more.
Note! Extraction capacity is a property of a motorized extractor hood that exhausts the air outdoors. This doesn't apply to recirculation range hoods or or motorless range hoods. The range hood you need depends on your home.
How do I calculate the required extraction capacity for my kitchen?
There is a handy calculation that helps you determine the amount of extraction capacity a range hood needs for your kitchen. It's important to distinct between a kitchen in a closed room, and an open kitchen.
** Separate kitchen **
Vacuum capacity = contents of your kitchen (length x width x height) x 10. This is the minimum extraction capacity you need to make your kitchen smell fresh again.
** Open kitchen **
If you have an open kitchen, calculating the minimum extraction capacity is a little more difficult. In this case, I recommend an extraction hood with a minimum extraction capacity of 600 m3 / hour.
A small kitchen has a maximum surface of 20m3. Because these kitchens aren't that large, you'll need a relatively small extraction capacity. A minimum extraction capacity of 200m3/h should be enough.
An average kitchen has a surface between 20 and 30m3. Depending on the surface of your kitchen, you'll need a range hood with a minimum extraction capacity between 200 and 300m3/h.
A large kitchen has a surface of 30m3 or more. Open kitchens also belong to this category. The minimum extraction capacity for these range hoods start at 300m3/h. For an open kitchen, go for a minimum of 600m3/h.
What else affects the extraction capacity?
- The extraction pipe: make sure the extraction pipe has a diameter of at least 150 millimeters. If the range hood extracts a lot of air and the pipe is too narrow, not all air will be extracted and you'll keep smelling those Brussels sprouts.
- Shape of the pipe: a pipe that's smooth and round is better at exhausting air. Make sure the pipe is properly clean on the inside.
- Outwards exhaust: the air has to be able to go outside as quickly as possible. For every bend in the pipe, you'll lose 73m3 of capacity. If you've got 4 bends in your pipe, that'll add up to a loss of 292m3. You'll also lose extra capacity for every extra meter of pipe, so make sure to keep the way out as short as possible.
- Size of your cooktop: the range hood has to be the same size, and preferably wider, than your cooktop in order to extract all fumes.
- Distance between cooktop and range hood: choose the right distance between the cooktop and the range hood. If the range hood is too low or too high, it won't work properly.