When sizing an exhaust fan for your kitchen, you must consider the location of the range, the size of the range (and hood, if you have one), and the size of your kitchen. It is important that your ventilation system meet the Cubic Feet per Minute (CFM) capacity as determined by the aforementioned factors. Otherwise, you will not properly exhaust odours, moisture, smoke, and other air contaminants, resulting in poor home air quality.

A ventilation fan should meet at least the minimum standard CFM to provide proper exhaust. According to the Home Ventilation Institute (HVI):

• a range against a wall requires 100 CFM per linear foot of range
• a range in an island requires 150 CFM per linear foot of range

If in doubt, refer to the rule of thumb: calculate 100 CFM for every 10 000 BTU of range, and you should have adequate ventilation. Just be sure to buy the right size for your space.