Electric Vs Gas Cooktops and How to Size your Range Hood

How big should my Range Hood or Vent Hood be?

In this article we will discuss why your choice of a range of hood depends on what type of cooktop you have. A range hood over an electric cooktop can be sized smaller in cfm output. And why a range hood over a gas cooktop should be sized larger than a similar width in an electric cooktop. Now most people think bigger is better, but remember, with a range hood, in most cases you are removing heated and air conditioned air along with your cooking odors and smoke. Sure you can turn your range hood on high and draw out 1200 cfm but if you live in phoenix in the middle of summer you have to air condition all the air that is getting sucked out of your house! The right size cfm range hood for the right cooking style and environment is important.

The right Range Hood or Vent Hood for Electric Cooktops

Many consumers use an electric cooktop and want the best Range Hood for their cooktop. The simple rule to follow is that you need 10 cfm of maximum air flow for each inch of width in your electric cooktop. So for example if your electric cooktop is 36” wide you need a maximum of 360cfm for your range hood. Now, this is much less than a similarly sized gas cooktop so if you want to know why this is the case then the details are below, but if you just want the fast and easy answer to the best size range hood for your electric cooktop, then there is the answer.

For Electric cooktops you will need 10 CFM for each inch of cooktop width.

One of the benefits of using an electric cooktop in your home is that there is no gas to burn to generate the cooking heat, so the burner output does not need to be exhausted by the range hood. In most cases an electric cooktop heats an element and this heat is transferred directly to the pan or griddle to accomplish the cooking. This means you can have a lower CFM range hood and still accomplish the removal of 100% of the cooking odors, steam and grease. The concept is very simple, with a gas cooktop, you burn Natural Gas or Propane that mixes with the oxygen in the air and quickly rises in the form of exhaust and heated air this must be removed and is generally removed with the steam and odors from the cooktop. As the hot air expands and rises quickly just the volume of exhaust from a gas cooktop will require a considerable amount of air to be removed to ensure that the cooking area maintains a constant temperature. Now gas cooktops have plenty of advantages that most people, especially serious cooks, are happy to buy and use the larger cfm Range Hood in order to accommodate their cooking style and the flexibility that a gas cooktop and a great Range Hood affords them. For more information about properly sizing your range hood for your gas cooktop please see our article on Range Hoods over a gas cooktop.

The right Range Hood or Vent Hood for Gas Cooktops

In today’s Kitchens the options for high output gas cooktops are plentiful. If you have a gas cooktop here is how to choose the right Range Hood for your gas cooktop. Depending on your cooking style and your setup, the most widely accepted standard to use to size your Range Hood or Vent Hood correctly for your gas cooktop is based on the total BTU’s produced by the cooktop. BTU’s are the Thermal Units that measure the amount of heat energy each burner, griddle or grill puts out at maximum output. This is important because with any gas cooktop or gas fired griddle or grill the fuel is Natural Gas or Propane. Both of these fuels will mix with air and burn to create the heat. The amount and intensity of the heat is based on the amount of fuel burned so the BTU’s are a good way to measure the maximum amount of CFM (Cubic Feet per Minute) of airflow you will need to move to effectively remove the Heat, Smoke, Odors and exhaust fumes that your stove will generate.

The standard rule is this:

The formula for how to size your Range Hood over a gas is you need 100CFM of airflow for every 10,000 BTU’s of heat energy. Now this is the basic formula and your own cooking style may need more or less depending on how you cook and the configuration of your cooking area. For example, if you are cooking greasy hamburger meat on a griddle in an island gas cooktop then you may need a higher CFM depending on how high the range hood is from the cooking surface. The coverage area, the CFM and the range hood height and design all play a big role in Range Hood performance.

Here is a typical example of how to size your Range Hood over a gas cooktop. Say the cooktop is a 48” Model with 6 burners and a griddle.

From the owners manual the small burners are 8,000 btu’s and the large burners are 12,000 btu’s and you have 3 of each for a total burner btu output of 60,000.

The griddle uses 20,000 btu’s. Total btu’s for the cooktop is 80,000 btu’s. This is a very realistic example and using our rule above of 100cfm for every 10,000 btu’s you would need a minimum size of range hood in the 800 cfm size.

Now, if your cooktop is in an island, and you have a grill that you will cook fish and steaks on, then you will need more cfm. Remember, when you are cooking with a gas cooktop against a wall the wall blocks any cross breezes, or air flows, and more importantly, helps confine the airflow that is drawn up. Other design factors play a big role in how to best size and select your new range hood so spend some time and study your cooking styles and make the choice that you feel is best for you. Thanks for reading and Happy Cooking! :-)

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