For about 60 years most Americans chose electric cooktops rather than the gas-fired type. The conventional wisdom was that electric appliances were easier to clean and the kitchen stayed cleaner as well. Once there was cause for such complaints. The reason: Exhaust systems were inadequate and gas residues remained to dirty kitchen walls, counters and ceilings and nearby furnishings. As exhaust devices improved and codes concerning their installation became law, the gas kitchen became a clean place to cook. Natural gas has always been better for cooking than its electrical counterpart because it gets hotter faster, it’s clean and it’s more cost-efficient than electricity – in most parts of the country.

Converting to a gas appliance can reduce your utility bill. But there are other considerations. Extending a gas line can cost more than the appliance itself. Also, modern, gas-fired appliances require electricity to power their electronic ignition system and any built-in lighting. The most important consideration, frequently overlooked, is a proper exhaust hood (range hood). Chances are the range hood that you used with your electric cooktop will not be sufficient to properly exhaust the additional gasses created by a gas appliance. Federal, state and local laws are rather specific in this area, so for safety's sake, make sure you purchase a range hood that is compatible with the cooktop you choose.

Even the best of range hoods can be noisy. By choosing the right size motor and fan type the sound level can be lowered. Better hoods use squirrel cage-type fans as opposed to the more familiar blade-type. The squirrel cage fan is cylindrical in shape and supported at both ends to minimize wobbling and noise. If the range hood is rated to exhaust more air than is required, be sure that it comes with a variable speed control. Most exhaust fans are quieter when they are not operating full blast.

Replacing the range hood can be a good idea even if the old cooktop isn't going to be replaced. Just disconnect the hood from the exhaust duct by removing a couple of strips of duct tape and one or two screws, disconnect the power lead, making sure power is off at the control panel, and remove the mounting screws that connect the hood to the cabinet. The mounting screws are usually located at the four corners of the hood and are sometimes hidden by an easily removable cover.

A range hood can be removed and replaced in less than an hour unless the new hood's exhaust port is a different shape from the old one. Some hoods have round exhaust ports and others have rectangular exhausts. This is solved by using a ready-made sheetmetal conversion boot. The addition of a conversion boot may require shortening the existing duct to make room for the adaptor.

In most instances the existing exhaust duct will be sufficient in size to handle the flow produced by a replacement hood. But, it is wise to check with the instructions that come with the hood before purchase. If you're a cooking fanatic and you want the best money can buy, look into a roof-mount motor assembly. The exhaust motor is mounted on the roof – not in the hood. Thus, motor noise is substantially reduced. Where a typical range hood will exhaust 200 cubic feet of air per minute (CFM) roof mounted units range from 600 CFM to 1,500 CFM and more. A 1,500 CFM model on high can remove a toupee.