Here is the single most important thing to understand about range hood installation: the install matters as much as the hood. A modest hood that’s mounted at the right height, connected to short, straight, correctly sized rigid duct, and vented properly outdoors will outperform an expensive 1,500 CFM hood strangled by flexible duct, three tight bends, and a mounting height six inches too high. Manufacturers rate airflow under ideal conditions; your installation is what decides how much of that rating you actually get. So the goal isn’t just to hang the hood on the wall—it’s to get four things right: correct height, correct duct, a proper outdoor termination, and safe power. This guide walks through the entire process in order, tells you honestly which parts are realistic to DIY and which aren’t, and shows you how to verify the job when it’s done. Whichever range hood you’ve chosen, this is how to make it perform.
Why installation determines performance
A range hood is a system, not an appliance. Air has to be captured over the cooktop, pulled through filters, driven by the blower, carried through the duct, and expelled outdoors—and the whole system performs at the level of its weakest link. Mount the hood too high and the plume spreads before it’s captured. Use flexible duct and turbulence eats your airflow. Undersize the duct and the motor works harder, gets louder, and moves less air. Terminate into an attic and you’ve created a grease and moisture problem while barely improving your kitchen air. None of those failures show up on a spec sheet; they show up in your kitchen every night. That’s why time spent planning the install pays back more than money spent on extra CFM.
Before you start: settle these six things
Almost every installation problem traces back to a decision that wasn’t made before the tools came out. Work through these first.
- Hood type and location. Under-cabinet, wall-mount (chimney), island, built-in insert, or downdraft—determined by where your cooktop sits and what’s above it.
- Width. The hood should be at least as wide as the cooktop; for wall-mount and island hoods, 3–6 inches wider per side improves capture. Measure the cooktop and, for under-cabinet installs, the cabinet opening.
- Mounting height. Most hoods are designed for 24–30 inches above the cooking surface (some allow up to 36). Confirm your model’s spec before anything else—it drives your cabinet and duct layout.
- Venting route. Horizontally through an exterior wall (simplest), vertically through the roof (needed for islands and central kitchens), or recirculating if no path exists.
- Duct size. Match it to your hood’s CFM and outlet: roughly 6″ up to ~600 CFM, 8″ for 600–900, and 8–10″ for 900–1,200+. Never reduce below the hood’s outlet.
- Power. Most residential hoods run on 120V; higher-CFM models (roughly 900+) may require a dedicated 15–20 amp circuit. Decide whether you’ll use an outlet or hardwire.
For the underlying technical requirements behind these—duct sizing tables, vent termination rules, and electrical specifics—see ROBAM’s range hood installation guide: duct, vent and electrical basics. This article focuses on the process itself.
Ducted vs. ductless: how the install differs
| Ducted install | Ductless install | |
|---|---|---|
| Work involved | Cut an opening, run duct, fit an exterior cap | Mount and power only |
| Typical time | Half a day to a full day+ | 1–3 hours |
| Skills needed | Cutting, ducting, sealing, often ladder/roof work | Basic mounting and electrical |
| Extra parts | Rigid duct, elbows, wall/roof cap, damper, foil tape | Charcoal filter |
| Config step | Set the hood to ducted; remove knockout if required | Set to recirculate; install charcoal |
If a vent path exists, duct it—the performance difference is substantial, especially for gas. Our ducted stove hood guide covers why. If you truly can’t duct, a convertible hood lets you recirculate now and duct later.
Tools and materials
Nothing exotic, but have it all before you start—a half-finished hole in your wall is a bad time to visit the hardware store.
- Measuring and marking: tape measure, level, stud finder, pencil, painter’s tape
- Cutting: drill with bits, hole saw, reciprocating saw or jigsaw, utility knife
- Fastening: screwdrivers, wrench set, mounting screws and anchors (usually supplied)
- Ducting: rigid galvanized or stainless duct, elbows, transition/adapter, exterior wall or roof cap with backdraft damper, foil (UL-181) tape or mastic, sheet-metal screws, tin snips
- Electrical: voltage tester, wire strippers, wire nuts, cable clamp
- Safety and finish: gloves, eye protection, dust mask, sturdy ladder, exterior-grade caulk, drop cloths
Safety first
- Kill the power at the breaker—not just the switch—and verify with a voltage tester before touching wiring.
- Shut off the gas if you’re working around a gas cooktop, and never disturb a gas line yourself.
- Know what’s inside the wall. Before cutting, check for studs, joists, wiring, plumbing, and—on exterior walls—anything on the other side.
- Protect the cooktop with a drop cloth or plywood; hoods are heavy and dropped tools crack glass.
- Use two people. Most hoods are awkward and heavy enough that lifting one solo is how they get dropped or misaligned.
The step-by-step process
Step 1 · Plan and mark the layout
Find the centerline of your cooktop and transfer it up the wall—the hood must be centered on the cooktop, not on the cabinet or the window. Measure up from the cooking surface to your model’s specified mounting height (typically 24–30 inches) and mark the hood’s bottom edge. Use a level: a hood installed even slightly out of level looks wrong forever and can affect how a chimney cover seats. Locate studs and mark them; the hood must anchor into structure, not just drywall. Then hold up the mounting template (most hoods include one) and mark your screw and duct-opening positions.
Step 2 · Cut the duct opening
Drill a small pilot hole through the wall or ceiling at the center of your intended opening and go look at where it emerges outside—this one habit prevents most catastrophic mistakes. Once confirmed, cut the opening to match your duct diameter (plus the clearance your instructions specify). Cut from inside out for cleaner drywall, and take care to avoid nicking cables or pipes. If you must pass a duct through a joist or stud, stop: that’s structural, and it needs a professional’s judgment rather than an improvised notch.
Step 3 · Run the duct
Assemble rigid, smooth-walled metal duct from the hood outlet to the exterior. Keep the run as short and straight as possible—under about 30 feet total, with no more than three elbows, and prefer two 45-degree bends to a single 90 where a turn is unavoidable. Never reduce the diameter below the hood’s outlet, and never substitute flexible or plastic duct. Point the crimped ends in the direction of airflow so joints shed grease outward, fasten each joint with sheet-metal screws, then seal every seam with foil (UL-181) tape or mastic—not standard duct tape, which fails with heat and age. Slope any horizontal run slightly toward the outside so condensation drains out, and insulate duct that passes through unconditioned or cold space to prevent condensation and dampen noise.
Step 4 · Install the exterior cap
Fit a wall cap or roof cap sized to your duct, with a working backdraft damper that opens under airflow and closes when the hood is off. Fasten it securely, then seal around the flange with exterior-grade caulk and, on siding, integrate with any flashing so water runs over—not behind—the cap. Skip the fine insect mesh: it clogs solid with grease and becomes the most common hidden cause of lost suction later on. For roof terminations, follow the 3-2-10 rule—the vent should rise at least 3 feet above the roof and stand 2 feet higher than anything within a 10-foot radius—and treat roof work as a professional job if you’re not equipped for it.
Step 5 · Sort out the electrical
Bring power to the hood location—either an outlet placed where the manual specifies (often inside the cabinet above) or a hardwire connection. Confirm the circuit suits your hood; higher-CFM models may need a dedicated 15–20 amp circuit. If a new circuit is required, or you’re not completely confident, this is the step to hand to a licensed electrician: it’s the part of the job where mistakes are both invisible and dangerous.
Step 6 · Mount the hood
Fit the mounting bracket (if your model uses one) into studs or solid blocking, checking level as you go. With a helper, lift the hood into position and secure it—don’t rely on drywall anchors alone for a heavy hood. Recheck level and centering on the cooktop before you tighten everything down. Under-cabinet models typically screw up into the cabinet bottom; wall-mounts use a wall bracket; island hoods hang from ceiling-mounted threaded rods or a support frame anchored to joists.
Step 7 · Connect duct and power, then finish
Connect the hood outlet to your duct with an adapter if needed, then screw and tape the joint. Make the electrical connection per the manual (matching hot, neutral, ground) and secure the cable with a clamp. Install the grease filters, add the charcoal filter if you’re recirculating, and fit the chimney cover or trim last—after you’ve tested, not before, so you’re not dismantling it to fix a rattle.
What changes by hood type
Under-cabinet
The most common and the most DIY-friendly: the hood screws into the cabinet above, and the duct either turns horizontally through the wall behind or rises vertically through the cabinet. Watch for cabinet-bottom thickness, and confirm the knockout or blower orientation matches your intended duct direction before mounting.
Wall-mount (chimney)
No cabinet above, so the hood carries its own weight on a wall bracket—anchoring into studs is non-negotiable. The visible chimney cover usually telescopes to your ceiling height; check that your ceiling falls within the model’s range, and order an extension if you have high ceilings.
Island
The most demanding install. The hood hangs from the ceiling and must be anchored to joists (often with added blocking), perfectly level and centered in two directions since it’s visible from every side. Ducting runs vertically through the ceiling and roof. Island hoods also need more airflow because there’s no back wall to funnel smoke—plan roughly 50% more CFM. For most homes, this is a professional job.
Built-in / insert
The unit sits inside custom cabinetry, so the cabinet must be built to the insert’s exact dimensions and clearances. Sequence matters: coordinate with your cabinetmaker before the cabinet is finished, not after.
Downdraft
Ducts down and out beneath the floor or through the base cabinet, which usually means coordinating with cabinetry and sometimes joists. Almost always a professional install.
Replacing an over-the-range microwave
This is one of the most common upgrades, and it’s usually a slot-for-slot swap—but check three things before you assume it’s easy. First, the existing duct: an OTR microwave is often recirculating, or ducted with a smaller 3¼″ × 10″ rectangular duct that a real hood will choke on. Second, the electrical: the outlet is typically in the cabinet above and may sit where your new hood needs the duct to pass. Third, mounting: hoods and microwaves anchor differently, and you’ll likely need to patch and repaint. The upgrade is well worth it—a dedicated hood ventilates far better—just budget for possible ductwork rather than assuming a 30-minute swap.
Make-up air: plan it during installation, not after
A powerful hood removes a lot of air, and in a tightly built home that air must be replaced or the hood pulls the house into negative pressure—which can drag combustion gases, including carbon monoxide, back down the flue of another gas appliance. Most codes require a make-up air system once a hood can exhaust more than 400 CFM, particularly where there are atmospherically vented gas appliances. A make-up air system uses a motorized damper that opens automatically when the hood runs. Retrofitting one later is far more disruptive than including it in the plan, so if you’re installing a high-CFM hood, resolve this at the design stage and check your local code.
Codes, permits, and inspection
Requirements vary by jurisdiction, so check locally before you start. In general: a simple like-for-like hood replacement on an existing duct and circuit often needs no permit, while new ductwork, a new exterior penetration, a new electrical circuit, or a make-up air system frequently does. The rules that matter most in practice are consistent—kitchen exhaust must terminate outdoors and never into an attic, soffit, or crawlspace; ducting must be smooth, rigid, non-combustible material; and hoods above the 400 CFM threshold trigger make-up air provisions. If you’re selling the home later, unpermitted structural or electrical work can surface during inspection, which is a good reason to do it properly the first time.
DIY or hire a professional? An honest breakdown
Plenty of people install an under-cabinet hood themselves and get an excellent result. Just as many discover halfway through that the duct route runs into a joist. Here’s a realistic split.
| Reasonable to DIY | Hire a professional |
|---|---|
| Swapping a hood onto an existing, correctly sized duct and circuit | Any new exterior wall or roof penetration |
| Under-cabinet mounting with an existing outlet | Island hoods and ceiling/joist anchoring |
| Ductless/recirculating installs | New or upgraded electrical circuits |
| Filter and chimney-cover fitting | Roof-level work of any kind |
| Ground-level exterior cap replacement | Make-up air systems; anything involving gas lines |
On cost: expect a straightforward ductless or like-for-like swap to be the cheapest scenario; ducted installs rise with the length and complexity of the duct route; and island or roof-vented installs plus new electrical sit at the top. Prices vary widely by region and by what’s behind your walls, so get itemized quotes rather than trusting a single number—and make sure the quote specifies rigid duct, the diameter, and the termination method. That detail is exactly where cheap installs cut corners.
Test it before you call it done
Commissioning takes five minutes and catches problems while the tools are still out.
- Run every speed and the lights. Confirm all controls work and the fan ramps smoothly.
- Paper test at the filter. On high, a sheet of tissue should be held firmly against the filter face.
- Check the outside. With the hood on high, confirm strong air at the exterior cap and that the damper flaps open—then close when it stops.
- Listen. Rattles usually mean a loose chimney cover, an unseated filter, or a duct joint that needs a screw.
- Feel for leaks. Run your hand along the duct joints; air escaping inside means a joint needs sealing.
- Smoke check. Boil a kettle under the hood and watch the steam—it should be drawn in cleanly rather than rolling out around the edges.
If any of that disappoints, diagnose it now rather than living with it—our troubleshooting guide walks through the causes in order.
Common installation mistakes to avoid
- Mounting too high to clear a backsplash or match cabinets—capture drops sharply beyond the specified height.
- Using flexible duct—turbulence kills airflow and the ridges trap grease.
- Reducing the duct diameter below the hood’s outlet to fit an existing hole.
- Too many elbows, or a long, winding route chosen for convenience.
- Venting into an attic or soffit—a grease, moisture, and fire problem.
- Sealing joints with cloth duct tape, which dries out and fails; use foil tape or mastic.
- Centering on the cabinet instead of the cooktop.
- Forgetting the venting configuration—leaving a ducted hood set to recirculate, or a recirculating hood with no charcoal filter.
- Ignoring make-up air on a high-CFM hood in a tight home.
- Installing the chimney cover before testing, then taking it apart again.
The bottom line
Range hood installation is where a good hood becomes a good ventilation system—or doesn’t. Get the height right, use short, straight, rigid duct sized to the hood, terminate fully outdoors with a proper damper, power it safely, and plan make-up air if you’re over 400 CFM. Do the easy parts yourself if you like, hand off the ducting, roof, and electrical when they’re beyond your kit, and test the result before you put the cover on. Done properly, the hood you chose will actually deliver what it promised—for the next decade.
Frequently asked questions
How high should a range hood be installed above the cooktop?
Most hoods are designed for 24 to 30 inches above the cooking surface, and some allow up to 36. Always follow your model’s manual: mounted higher than specified, the plume spreads before it’s captured and no amount of CFM fully compensates; mounted too low, you risk heat damage.
Can I install a range hood myself?
Often yes for a like-for-like swap onto an existing, correctly sized duct and circuit, or for a ductless install. Bring in a professional for new exterior penetrations, roof work, island hoods, new electrical circuits, make-up air systems, or anything involving gas lines.
What size duct do I need for a range hood?
Match it to the hood’s airflow and outlet—roughly 6″ up to about 600 CFM, 8″ for 600–900 CFM, and 8–10″ for 900–1,200+ CFM. Use rigid, smooth-walled metal duct, and never reduce below the hood’s outlet size to fit an existing hole.
Do I need a permit to install a range hood?
It varies by jurisdiction. A simple replacement on existing duct and wiring often doesn’t require one, while new ductwork, a new exterior vent, a new circuit, or make-up air frequently does. Check with your local building department before starting.
Can a range hood vent into the attic?
No. Kitchen exhaust must terminate fully outdoors through a wall or roof cap. Venting into an attic, soffit, or wall cavity deposits grease and moisture in an enclosed space, creating mold and fire hazards—and it barely improves your kitchen air.
How long does range hood installation take?
A ductless or straight replacement can take one to three hours. A new ducted install through an exterior wall typically takes half a day to a full day, and island or roof-vented installs with new electrical can take longer—especially if walls or cabinetry need modification.
Can I replace an over-the-range microwave with a range hood?
Usually yes, and it ventilates far better. Check the existing duct first—OTR microwaves are often recirculating or use a small rectangular duct that a real hood will choke on—plus the outlet position and mounting differences. Budget for possible ductwork rather than assuming a quick swap.
Installation, duct sizing, termination, and make-up air guidance reflects widely used kitchen-ventilation best practices; codes and permit requirements vary by jurisdiction, so confirm with your local building department. Always follow your model’s installation manual, switch off power at the breaker and verify with a tester before wiring, and use licensed professionals for electrical, gas, structural, roof, and combustion-safety-sensitive work. This article is for general informational purposes.
