What You Need to Know Before You Start

Installing a range hood vent yourself is possible if you have basic tools and are comfortable working at ceiling height, but the job involves three separate tasks: mounting the hood to the wall or cabinet, running ductwork to the outside, and making electrical connections. The hardest part is usually cutting through the exterior wall or roof to vent to the open air—that step determines whether the whole project takes a weekend or requires a contractor. If your kitchen has no existing ductwork and you would need to cut through brick, stone, or a load-bearing wall, hire a professional. If you have a clear path to an exterior wall or soffit, you can do this yourself.

The process differs slightly depending on whether you are installing an under-cabinet hood (mounted directly to the cabinet above the stove), an island hood (hanging from the ceiling), or a wall-mounted hood (attached to the wall). This guide covers under-cabinet installation, the most common type. You will need to turn off power to the circuit before you begin, and you should have a helper for the heavy lifting.

Key Takeaways

  • Turn off the circuit breaker to the hood location before you start any work, and test the outlet with a voltage tester to confirm power is off.
  • Mount the hood securely to the cabinet frame using the mounting brackets and hardware that come with the unit, checking level in both directions.
  • Run ductwork from the hood outlet to the exterior wall or soffit, using the shortest, straightest path possible and sealing all joints with foil tape.
  • Make the electrical connection by wiring the hood to a dedicated outlet or hardwiring it to the circuit, depending on your hood model and local code.
  • Test the hood and damper before you finish, and seal any gaps around the exterior vent opening with caulk to prevent air leaks.

Gather Your Tools and Materials

Before you buy the hood, measure the width of your cooktop and the distance from the cooktop surface to the bottom of the cabinet above it. Most hoods are 30, 36, or 42 inches wide and need at least 24 inches of clearance above the cooking surface. Check your hood's manual for the exact ductwork diameter—most use 6-inch round or rectangular duct.

You will need a drill with bits, a stud finder, a level, a tape measure, a voltage tester, wire strippers, and a screwdriver set. For ductwork, buy rigid aluminum duct (stronger and quieter than flex duct) in the diameter your hood requires, plus elbows, a wall cap or roof flashing, and foil tape. If you are hardwiring the hood, you will also need electrical wire in the gauge specified by your hood's manual (usually 12 or 14 gauge) and wire nuts. If the hood plugs in, make sure there is an outlet within reach of the power cord, or plan to install one.

Turn Off Power and Mount the Hood

Locate the circuit breaker that controls the outlet or hardwired connection where the hood will plug in or connect. Switch it off, then use a voltage tester on the outlet or wires to confirm there is no power. This is not optional—range hoods draw significant current and working on a live circuit is dangerous.

Position the hood under the cabinet and use the mounting brackets (included with the hood) to find it to the cabinet frame. Most brackets bolt to the sides of the hood and screw into the cabinet frame from underneath. Have your helper hold the hood level while you mark the screw holes with a pencil. Use a level to check that the hood is straight in both directions—left to right and front to back. Drill pilot holes, then drive the screws. Do not tighten them fully until the hood is level and all brackets are in place.

Once the hood is mounted, check that it sits at the correct height above your cooktop. Most manufacturers recommend 24 to 30 inches from the cooking surface to the bottom of the hood. If the height is wrong, loosen the brackets and adjust before tightening everything down.

Run Ductwork to the Exterior

The ductwork path is the most important part of the installation. Trace the shortest, straightest route from the hood outlet to the exterior wall or soffit. Avoid running duct through walls, attics, or crawl spaces if possible—every bend and every foot of duct reduces airflow and increases noise. If you must run duct through a wall cavity, use rigid duct and seal every joint with foil tape.

If you are venting through an exterior wall, locate a stud bay (the space between two studs) and mark the center point on the outside of the wall. Drill a pilot hole from inside, then go outside and drill a larger hole for the wall cap. The hole diameter should match your ductwork diameter. Use a drywall saw or hole saw to cut the opening from inside, then push the ductwork through and attach the wall cap on the outside with the flange sealed to the siding with caulk.

Connect the ductwork from the hood outlet to the wall cap using elbows as needed. Seal every joint—where the duct connects to the hood, where elbows meet duct, and where the duct enters the wall cap—with foil tape. Wrap the tape around the joint twice to may support a tight seal. Do not use duct tape; it degrades over time and will fail.

Check that the damper (a flapper inside the wall cap) moves freely. The damper should open when the hood runs and close when the hood is off, preventing outside air from flowing back into your kitchen. If the damper is stuck, clean it or replace the wall cap.

Make the Electrical Connection

How you connect power depends on your hood model. Some hoods come with a power cord and plug into a standard outlet. Others are hardwired directly to the circuit. Check your hood's manual to see which type you have.

If your hood plugs in, make sure the outlet is within reach of the power cord and is on a dedicated 120-volt circuit. If there is no outlet in the right location, you will need to install one. This requires running new wire from the breaker panel, which is beyond the scope of a basic installation—hire an electrician.

If your hood is hardwired, turn off the breaker again and test with a voltage tester to confirm power is off. Remove the cover plate from the junction box on the hood. Run the electrical wire from the breaker panel to the junction box (or have an electrician do this). Strip about 3/4 inch of insulation from each wire, then connect the black (hot) wire to the black wire in the hood, the white (neutral) wire to the white wire, and the bare copper (ground) wire to the green screw or bare wire. Use wire nuts to find each connection, twisting clockwise until tight. Tuck the wires into the junction box, replace the cover plate, and turn the breaker back on.

Test the Hood and Seal Gaps

Turn on the hood and listen for unusual noises. The motor should run smoothly without rattling or grinding. Check that air is flowing out of the hood—hold your hand near the cooktop and you should feel suction pulling air upward. If there is no airflow, check that the damper is opening and that the ductwork is not kinked or blocked.

Go outside and inspect the wall cap. Make sure the damper opens when the hood is running and closes when it is off. If the damper is stuck, turn off the hood and clean any debris from the damper flap.

Seal any gaps around the wall cap on the outside with exterior caulk. This prevents rain and outside air from entering your kitchen. On the inside, seal the gap between the ductwork and the hole in the wall with caulk or foam sealant. Do not leave gaps—they reduce efficiency and allow drafts.

Common Mistakes to Avoid

The most common mistake is using flex duct instead of rigid duct. Flex duct is cheaper and easier to route, but it has a corrugated interior that traps grease and reduces airflow. Use rigid duct whenever possible. If you must use flex duct, keep runs short and support it every 3 feet with a strap.

Another mistake is running ductwork with too many bends. Each elbow reduces airflow by about 10 percent. Plan your route to minimize turns, and use 45-degree elbows instead of 90-degree elbows when you can—they create less resistance.

Do not skip sealing the ductwork joints. Unsealed joints leak air and reduce the hood's ability to pull smoke and steam out of your kitchen. Use foil tape on every connection.

Finally, do not forget to check local building codes before you start. Some areas require a permit for range hood installation, and codes may specify ductwork size, venting location, or electrical requirements. Call your local building department to confirm what applies in your area.

Frequently Asked Questions

Can I vent the hood into the attic instead of outside?

No. Venting into the attic dumps moisture and cooking odors into an unvented space, which causes mold, rot, and structural damage over time. All range hoods must vent to the outside air. Some building codes explicitly prohibit attic venting and will not issue a permit for it.

What if I cannot find a clear path to an exterior wall?

If your kitchen is in the center of your home or far from an exterior wall, you have two options: run ductwork through the attic to a soffit or roof vent (the longest, least efficient route), or hire a contractor to cut through a wall or roof. A professional can also help you navigate local codes and permits for venting through a roof or masonry wall.

Do I need a dedicated circuit for the hood?

Most building codes require a dedicated 120-volt circuit for a hardwired range hood. A dedicated circuit means the hood is the only appliance on that breaker. If your hood plugs in, it can share a circuit with other outlets, but it is safer to give it its own. Check your local code and your hood's manual.

How often should I clean the ductwork?

Clean the hood filter every month or every 60 hours of use, whichever comes first. The ductwork itself should be inspected once a year for grease buildup, especially if you cook frequently. If you see grease inside the duct, hire a professional duct cleaning service—cleaning ductwork yourself is difficult and can damage the duct.

What is the difference between a damper and a backdraft preventer?

A damper is a flapper inside the wall cap that opens when the hood runs and closes when it stops. A backdraft preventer is a more sophisticated version with springs or magnets that seal more tightly. Both prevent outside air from flowing back into your kitchen. Most wall caps include a damper; if yours does not, you can buy a separate backdraft preventer and install it in the ductwork.