Installation guide: Venting a range hood may require a bit of engineering because the stove is not always near a window or along an outside wall. You can't vent a range into an interior wall or an attic, for example, because there's always a chance of starting a fire. Plus, the odors that build up can attract insects, and the heat and moisture can create mildew and mold. If your kitchen can't accommodate a vented hood, you'll need a ventless model.
Operating manual: A ventless hood filters the air above your stove through a medium like charcoal, which absorbs odors and smoke as you cook. But these filters are not maintenance-free; they should be replaced regularly, following the manufacturer's instructions.
All range hoods have grease filters that should be cleaned regularly; most can be placed in the dishwasher, following the maker's guidelines.
Be sure to ask: How loud is the fan? Hoods must make noise to work, but producers are making major efforts to keep the sound of air-cleaning to a minimum. Sound is measured in sones. For comparison purposes, newer-model refrigerators are designed to produce one sone, talking in a normal tone of voice is about four sones, and the sound of an airplane landing measures 225 to 250 sones.
Power play: The more powerful the range hood's fan, the noisier it will be. A fan's ability to move air is measured in cubic feet of evacuated air per minute. The kind of fan will be one determinant of the noise level. A centrifugal fan will move more air and do it more quietly, but a rotary fan will be less expensive. You should buy a hood with a choice of fan speeds, because boiling beans doesn't require the same level of air cleaning as broiling a steak.
Size matters: The hood must be at least as wide as the range or cooktop - 30 to 60 inches. If you're installing the hood yourself - some mount on the wall, some under a cabinet, and some can go both places - make sure it can be done according to the height specifications required by the manufacturer.
Style file: Stainless steel seems to be the primary material for range hoods, though some makers offer panels decorated with glass or ceramic tile that can be fitted onto the steel structure of the hood. Still others feature concrete and plaster adornments.
See the light: Consider the range hood's light when you're looking at various models and make sure it provides a lot of illumination. Bulbs should be easy to reach for cleaning and replacement, and readily available at home centers or hardware stores (not just on Web sites).
Bells and whistles: Manufacturers are developing hoods that can be expanded at the touch of a button, such as Thermador's new chimney-style hood with a slide-out canopy that extends up to an extra 12 inches, for 45 percent more coverage of the cooking area. Best by Broan models detect excessive heat and adjust fan speed automatically, to prevent accidents.
What will it cost?Prices are all over the board, although $300 to $4,000 gives a good idea of the spread. A ventless hood with a variable-speed rotary fan will cost less; a hood that's also an art object, more.
Want Alan J. Heavens' advice on a home-improvement project or purchase? E-mail him at email@example.com or write to him at The Inquirer, Box 8263, Philadelphia 19101.