How to Install Ducted Range Hood? | Vent Installation Guide

Range hoods that recirculate air back into the kitchen leave grease on cabinets and moisture in the drywall. A ducted hood that actually vents outside solves both problems — but only if the duct path, seals, and electrical connections are right. This guide covers how to install a ducted range hood, from cutting the wall penetration to wiring the unit, with the code-approved steps that keep the system moving air and not leaking heat.

Tools and Materials Needed for the Job

A ducted hood install needs more than the hood itself. You will need a drill/driver, oscillating tool or reciprocating saw, drywall saw, screwdrivers, wire strippers, a level, tape measure, stud finder, and a long drill bit (for marking the exterior wall). The materials list includes 8-inch round rigid smooth metal duct (not flexible foil), 6-to-8-inch reducer if the hood collar is smaller, metal foil tape or mastic, rivets or external draw bands, a roof or wall vent cap with a built-in backdamp damper, PVC trim board (for siding), fire-rated caulk, duct insulation, 14/2 or 12/2 electrical cable, wire connectors, and a junction box rated for the hood’s amperage.

Professional installation typically runs $500–$1,500 depending on duct path complexity and whether an electrician is needed. DIY material costs land between $150 and $400 for the duct, cap, and hardware.

Installing a Ducted Range Hood: The Step Order That Works

Follow this sequence to avoid cutting the wrong hole or wiring the unit into a wall you already patched. Each step builds on the one before it.

1. Disconnect power and remove the old hood. Flip the breaker for the existing circuit, then disconnect the wiring and unbolt the old unit. If the new hood arrives weeks before installation, cover and seal all its openings to keep dust and drywall debris out of the blower and electronics.
2. Mark the vent center using the paper template. Most hoods ship with a paper template that shows the exact hole position. Tape it to the wall centered above the stove and mark the center of the vent circle. Use a stud finder to check whether a stud runs through that spot.
3. Cut the interior hole. Cut a 6-inch (minimum) hole through the drywall and sheathing with an oscillating tool or reciprocating saw. If a stud occupies the space, cut a larger opening and frame a new stud bay rather than cutting through a load-bearing member without reinforcement.
4. Transfer the hole location to the exterior. Drill four locator holes through the sheathing from inside the hole, one at each compass point. Go outside, connect the dots, and cut the exterior opening. If the siding is rough, cut a square PVC trim board, drill the 6-inch hole through it, then mount the trim board as a clean base for the vent cap.
5. Run the rigid metal duct. Attach the first section of 8-inch round smooth metal duct to the hood’s exhaust collar using sheet-metal screws and metal foil tape. Run the duct vertically through the ceiling or horizontally through the wall toward the exterior cap. Keep the path as straight as possible — each 90-degree turn cuts airflow efficiency by up to 20%. Use two 45-degree fittings to turn a corner when needed.
6. Seal and insulate every joint. Apply metal foil tape or mastic at every duct joint, adaptor, and connection. Never use standard duct tape — it degrades with heat and fails within months. Mechanically fasten each joint with rivets or external draw bands; sheet-metal screws are acceptable but less preferred. If the duct runs through an unconditioned attic or crawlspace, wrap it with duct insulation to prevent condensation in cold weather.
7. Install the exterior vent cap. Mount the wall or roof cap so the backdraft damper opens upward and outward. Caulk around the cap flange with exterior-grade sealant to keep rain and pests out.
8. Mount the hood. With a second person holding the unit, insert screws through the mounting slots. Tighten the upper screws first, then check with a level before fully tightening the lower ones. The hood must sit level — even a slight tilt changes airflow direction across the cooktop.
9. Wire the hood to a dedicated circuit. Run 14/2 or 12/2 cable from the breaker to the hood’s terminal box. Connect white to white, black to black, and the bare copper ground to the ground screw. Use wire connectors and clip any excess wire so the connections sit neatly inside the box. The circuit should serve only this hood — sharing with other appliances can trip the breaker when the fan and lights run together.
10. Install the fan motor, filter, and test. Reinstall the blower and grease filter. Turn the power back on at the breaker, then test every fan speed and the lights. Go outside and confirm strong airflow exits the vent cap and that the damper opens fully without sticking.

What Duct Materials Does Code Require?

Current US building codes (2021/2024 editions) mandate rigid smooth metal ductwork for any ducted range hood. Flexible foil or plastic duct is explicitly prohibited because it traps grease and restricts airflow. The table below summarizes the code-compliant specs for every part of the duct run.

Lowe’s official range hood installation guide provides step-by-step photos for cutting the hole and mounting the unit. Check local amendments before starting — some municipalities require larger duct diameters or makeup air systems for hoods above 600 CFM.

If you are still shopping for the right unit, our roundup of the best ducted range hoods for gas stoves compares top models by CFM, noise rating, and filter type to help you choose before you start cutting holes.

Common Mistakes That Undo a Good Install

Even a well-chosen hood performs poorly if the duct run or sealing is off. The table below lists the five most frequent errors found by home inspectors and the straightforward fix for each.

Final Testing Before Closing the Walls

Once the hood is mounted, wired, and ducted to the exterior, run the fan on its highest speed and hold a piece of tissue paper near the grille. The paper should pull firmly against the mesh — that confirms the duct path is clear, the seals hold, and the damper opened fully. If the paper flutters or falls, check for a blocked damper, a crushed duct bend, or a joint that was taped but not mechanically fastened. Seal ceiling and wall penetrations with fire-rated caulk, insulate any duct runs in unconditioned space, and only then patch the drywall. A hood that tests weak now will only perform worse once the walls are closed and the attic insulation is in place.