What Does a Range Hood Do? | Kitchen Air, Handled

Walk into any kitchen that’s had a decade of cooking and no ventilation, and you’ll notice the sticky film on the cabinets and the lingering smell of last night’s fish. That’s what a range hood prevents. It’s the appliance above your cooktop that pulls airborne cooking byproducts—smoke, grease, moisture, heat, and odors—out of the air you breathe. Whether it ducted outside or recirculates through filters, its job is the same: keep your kitchen air cleaner and your surfaces from getting coated in grease.

Ducted vs. Ductless: What’s The Difference?

The biggest choice you’ll make is whether your hood vents outside or recirculates the air. A ducted hood pushes smoke and grease through ductwork to the exterior of your home, which makes it the best-performing option for ventilation. A ductless hood, also called a recirculating hood, passes air through filters—one for grease and a carbon filter for odors—and sends it back into the kitchen.

That difference matters more than you’d think. Ductless systems don’t remove air or humidity from the home; they clean it and put it back. If you do a lot of high-heat cooking, a ducted hood is the more effective choice. If you can’t run ductwork through your walls, a good ductless model with fresh carbon filters still handles everyday smoke and smells well.

Matching the hood to your cooking style and your kitchen’s layout is the core of the whole decision. our tested roundup of wood range hoods walks through the best of both types.

How Much Power Do You Need?

Hood strength is measured in cubic feet per minute, or CFM. It’s simply how much air the fan moves. Most residential hoods fall between 200 and 600 CFM, and for many kitchens, 300 to 600 CFM is plenty. To find your number, you first figure out your kitchen’s volume in cubic feet (length × width × ceiling height), then aim for enough fan power to change that air about 10 or 12 times an hour, as recommended in buying guides.

For gas cooktops, there’s an easier rule of thumb: roughly 100 CFM for every 10,000 BTUs your burners put out. A 40,000-BTU range, for instance, would want around 400 CFM. Electric cooktops don’t produce combustion byproducts, so they need less power.

One more spec worth noting from the Home Ventilating Institute’s guide: a hood should be at least as wide as your cooktop, ideally extending about three inches on each side. That extra width catches the smoke before it drifts past the fan.

What’s The Right Mounting Height?

Height is where a lot of hoods underperform. If it sits too high, the fan can’t catch the rising smoke; too low and it gets in the way of tall pots. The commonly cited rule is to keep the bottom of the hood no more than 36 inches above the cooktop. For gas ranges, check your manufacturer’s clearance requirement, since the BTU output and burner design affect where the hood should sit to capture effectively.

The standard depth for most hoods is 22 inches, which aligns well with typical 24- and 30-inch ranges. And the 30-inch width is the most popular size for both electric and gas cooktops, so if you’re replacing an older unit, that’s the safest bet for a standard cutout.

Using the hood matters as much as buying it. Run it before you start cooking to get the air moving, keep it on while you cook, and leave it running for a few minutes after you finish to clear lingering moisture and odors.

FAQs

Do I really need a range hood for an electric stove?

Yes, though the reason shifts. Electric cooktops don’t produce combustion gases, but they still generate steam, grease, and odors, especially at high heat. A hood keeps those from settling on your cabinets and counters. A ductless model with a good grease filter will handle this fine for most electric kitchens.

How often should I replace the carbon filter?

Carbon filters in ductless hoods stop absorbing odors once they’re saturated, so they need regular replacement—typically every three to six months depending on how much you cook. The grease filter, meanwhile, should be cleaned monthly; many are dishwasher-safe. If your kitchen starts holding onto cooking smells, it’s usually a sign the carbon filter is done.

Can a range hood remove smoke from a burnt dish?

Yes, a well-sized hood will clear burnt-food smoke quickly, but it has to be running before things get bad. Crank the fan to its highest setting right as the smoke appears. A ducted hood clears the room faster than a ductless one; a ductless hood filters the smoke but takes longer to scrub the air.