When choosing a range hood exhaust fan, ensure it is rated at least 150 to 300 cubic feet per minute to properly vent an electrical range, suggests KitchenSource.com. To size the fan for a gas range, add the amount of British thermal units that each burner creates and divide by 100 to determine the amount of cubic feet per minute the fan should exhaust.
For professional gas ranges, the total British thermal units divided by 100 is a good rule of thumb, but if the duct work is particularly long and contains several 90 degree bends, size up the fan. If the range hood is not larger than the actual range, consider purchasing a larger fan. An exhaust hood located several feet above the range may also merit a stronger fan. Purchasing a more powerful fan also allows cooks the option of running the fan at a lower setting, which is often quieter. If an electric range has a built-in deep fat fryer, use the gas range method to calculate the required fan size.
Centrifugal blowers and air ring fans are the two types of fans used in range exhaust hoods. Centrifugal blowers, also called squirrel cage blowers, have a paddle-shaped fan that forces air upward. They are more efficient and quieter. Air ring fans are louder but more economical.