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My wife and I were in a showroom deciding on cabinets for an upcoming kitchen renovation when I told our kitchen designer that the vent hood was, for me, the most important part of the new kitchen. The designer thought I was kidding. Awkward laughing ensued.

To fixate on venting, when there are dozens of other decisions to make—from cabinet door shape to countertop color—might sound trivial. But, I’ve never had a kitchen that vented smoke and smells to the outside. Instead I’ve had recirculating hoods mounted above the range, or the popular microwave-fan combo. As an avid home cook, I don’t love either option.

I wanted a powerful vent that blended in with the rest of the kitchen. That meant covering the gleaming expanse of steel with cabinetry for a beautiful, seamless look. Want to do the same? Here’s what you’ll need to consider when buying an insert and the cabinet that hides it.

What is it?

Sure, a vent hood yanks odors out of the kitchen, but it also expels grease, nitrogen dioxide, carbon monoxide, and the moisture released while cooking. Research shows that cooking without ventilation causes poor indoor air quality. The U.S. Environmental Protection Agency advises homeowners to install a vent to pull fumes outside, usually through the roof or an exterior wall.

How much does it cost?

There are two main parts to a kitchen vent, often called an insert or a power pack system: the liner and the blower. Prices vary for both depending on size, which can range from 30- to 60-inches wide—anything larger is usually a custom order. Liners start at about $50 for a basic rectangle, and a few bucks more for a T-shape style (the shape depends on the cabinetry you pick). Blowers, which are built into metal enclosures that also house the grease filters and fan and light controls, start at about $250. A piece of cabinetry covers both parts.

Rounding out the system is galvanized steel ductwork, usually 6 or 7 inches in diameter, that escorts air outside through the kitchen wall or ceiling. Home centers stock the ductwork, which cost about $1.50 per linear foot, and the elbows you’ll need to make the connection to the blower. Beyond that, plan on spending around $50 for various elbows and the decorative vent cap that installs on the wall or roof.

DIY or hire a pro?

If the location isn’t moving on the wall, replacing a recirculating fan with an exhaust vent requires basic electrical work to connect the wiring. Running the ductwork is simpler if the vent is mounted on an exterior wall. Consider hiring a pro to vent through the roof. Either way, hiding a vent behind a piece of cabinetry starts with adding the new decorative wood cover.

Where to buy?

You can order inserts at home centers and appliance retailers.

What about maintenance?

Manufacturers recommend cleaning the filters after every 30 hours of use—about every two months—to keep a fan running smoothly.


Other things to know

Sizing up your power needs.

All vents are labeled with a cubic feet per minute (cfm) rating, which measures how much air they move out. When it comes to finding an insert with the right amount of power, use this cheat sheet: For standard cooktops and ranges, calculate 100 cfm for every linear foot of cooking surface. For high-end, pro-style ranges (greater than 60,000 BTU), use 100 cfm for every 10,000 BTUs the appliance generates. Typically, the vent is installed 22 to 30 inches above the cooktop. For every 3 inches the vent is beyond 30 inches from the cooktop, add 100 cfm.

Dial in the measurements.

An insert, and the cabinet hood that hides it, should be at least as wide as your cooking surface. Matching wood hood widths typically start at 30-inches wide and move up, in 3-inch wide increments, up to 84 inches. If you have room, and budget, adding an extra 3 inches to the insert on each side can improve venting efficiency. For depth, the hood should cover half of the front burners and all of the ones in the back.

Check the noise level.

Check the sone rating before buying—it’s a specification most vent manufacturers include—and look for appliances carrying the Home Ventilating Institute (HVI) certification. 1 sone is equivalent to about 40 decibels and while a fan set on low can be under a sone, it can jump to 10 or more on high. Look for an insert that is 8 or fewer sones at 600 cfm.

Install the cabinet first, then the vent.

After our kitchen cabinets were delivered, our general contractor installed the wood hood. Our new two-piece Broan insert and hood (shown above) replaced our existing recirculating fan, meaning we didn’t have to move wiring. Our wood hood was finished in the same color and style as the cabinetry and cost us about $300 (chimney style hoods, which are also an option when hanging the vent on the wall, typically start at $2,000 for the cabinetry and about $700 for the vent).

Like most kitchen layouts, the hood is sandwiched on the wall between two upper cabinets. The hood itself is really more of a false front: a U-shaped design with a front panel held in with clips that allows access to the motor. Our general contractor fixed the hood in place by screwing through the stiles of the upper cabinets flanking it.

Once the wood hood is in place, the liner—a T-shaped version in our case—slips in from underneath and attaches to the side of the neighboring wall cabinets with short screws. Next comes the blower, which pass through the rectangular opening in the liner from below. Here’s where the false front hood panel is helpful. Once the blower is in and held in with clips that support its weight, you’re free to let go and reach in and make the wiring connections.

With the fan in place my contractor cut a hole in the wall to accommodate the ductwork. He used a combination of 45- and 90-degree elbows to go through the stove wall, and over the joists in the garage just on the other side of the kitchen. From there it was a straight run across the garage and out the exterior wall where a vent cap finished the ductwork off. He taped the seams with foil tape, boxed the ductwork in a drywall chase, per code, and filled the gap around the pipe penetration in the stove wall with orange, fire-blocking polyurethane spray foam.

Here are a few tips when it comes to putting together an efficient ductwork layout:

Most inserts have a 6-inch diameter opening, but increasing to 8-inch (or larger) pipe helps move more air around tricky turns and corners. We used fittings that go from 6 to 8-inches if you want to beef up the ductwork. A typical 400-cfm unit requires a 6-inch duct, but a heavier duty a 1,200-cfm model would need a 10- to 12-inch duct. Keep the runs of duct as straight and short as you can and use gradual, 45-degree turns rather than hard 90-degree ones. Anytime you’re moving air, the fewer the turns, the more efficient the system will be. Always opt for smooth galvanized metal ducting over flexible or corrugated ducting, and seal joints with duct-joint foil mastic tape (not ordinary duct tape, which will dry up and fall off).