Range Hood Installation in a Kitchen: A DIY Guide

The short version: a DIY range hood install is doable in a weekend if you're replacing an existing hood on the same circuit and duct run, but a brand new ducted install involves cutting into exterior walls or roofs, running new wiring, and sizing ductwork, and that's where most DIYers either give up or end up with a hood that looks fitted but does nothing. Know which job you're doing before you buy the hood, not after.

I'm a marketing and AI consultant, not a tradesperson, so I won't pretend I've got grease on my hands from a hundred installs. What I'm good at is pulling apart a job into the steps that matter and telling you where people waste money or time. Range hoods are a classic case of a "simple" home job that turns into a weekend of swearing because nobody told you the duct size changes everything.

The two jobs hiding inside "install a range hood"

There isn't one DIY range hood job, there are two, and they're not the same difficulty.

• Like-for-like swap: you're replacing an old hood with a new one of a similar size, in the same spot, using the existing duct and existing electrical connection. This is a genuine weekend DIY job for most people.
• New or relocated install: you're adding a hood where there wasn't one, moving the position, switching from under-cabinet to a bigger canopy, or going from a non-vented hood to a fully ducted one. This involves cutting through cabinetry, walls, or roofline, and in most places it also means an electrician for the new circuit. This is not a Saturday afternoon job, it's a multi-day project and often not solo DIY.

Say you're planning to swap a tired 30-inch under-cabinet hood for a new one in the exact same spot. That's job one. Say you're ripping out a dated kitchen and putting a 36-inch canopy hood over an island where there's currently no duct at all. That's job two, and it's the one where YouTube videos make it look faster than it is.

Tools and parts you need before you start

For a straightforward like-for-like swap, here's what's on the list:

• Stud finder
• Drill driver with a range of bits
• Screwdrivers (flat and Phillips)
• Adjustable wrench
• Tape measure and a spirit level
• Wire connectors and a wire stripper, if the new hood's wiring differs from the old one
• Foil duct tape (not cloth duct tape, it degrades with heat)
• Jigsaw, if you need to enlarge a cabinet cutout
• A second pair of hands, because range hoods are awkward, not heavy, and holding one overhead while you line up mounting screws is a two-person job

Step by step: a like-for-like hood swap

Here's the realistic sequence for swapping an existing ducted hood, assuming the duct and vent position are staying put.

1. Turn off the power at the breaker, not just the wall switch. Test with a voltage tester before touching any wires. This is the one step people skip and it's the one that puts people in A&E.
2. Remove the old hood. Disconnect the duct connector, undo the mounting screws (usually two to four, through the bottom of the upper cabinet or into a wall bracket), and disconnect the wiring.
3. Check the duct size. Most residential hoods use either a 3.25 x 10 inch rectangular duct or a 6-inch round duct. If your new hood's duct outlet doesn't match the existing ductwork, you need a transition adaptor, and this is where a lot of installs stall because the box doesn't mention it.
4. Mount the new bracket or template as per the manufacturer's instructions, using the stud finder to make sure screws are going into solid wood, not just drywall or thin cabinet base.
5. Connect the wiring using wire connectors, matching black to black, white to white, and ground to ground, then tuck the connections into the junction box provided.
6. Attach the duct connector and seal every joint with foil tape, not just push-fit. Unsealed joints lose a meaningful chunk of the hood's extraction power before the air even leaves the house.
7. Lift the hood into place with your second pair of hands and secure the mounting screws.
8. Restore power and test all fan speeds and the light before you put the filters back in.

Budget half a day for this if everything matches, a full day if you hit a duct size mismatch or discover the old wiring is in worse shape than you thought, which happens more often than any tutorial admits.

The bit most guides gloss over: CFM and duct sizing

Here's where I'll say the thing most DIY articles skip past because it's less exciting than "drill four holes and you're done." A range hood is rated in CFM (cubic feet per minute), and the duct run it's connected to has a maximum CFM it can carry before the fan is working against itself. A 6-inch round duct tops out at roughly 400 CFM in practice once you account for bends and length. If you buy a 600 CFM hood and run it through a 6-inch duct with two 90-degree bends and a 15-foot run, you have not bought a 600 CFM hood. You've bought a loud box that moves air at a fraction of its rating and leaves grease and steam sitting in the kitchen.

The rule of thumb used by most ventilation guidance is 100 CFM per linear foot of cooktop, so a 30-inch (2.5 foot) range wants around 250 to 300 CFM minimum, more if it's a gas range with high-BTU burners. But that number is meaningless if the duct can't carry it. Before you buy a hood, measure your actual duct run: diameter, length, and number of bends. If you're stuck with an old undersized duct and don't want to replace it, buy a hood rated for what that duct can deliver, not the biggest number on the box. A smaller hood that's matched to its ducting will outperform a bigger one choked by a bad run, every time, and nobody selling you the hood is going to tell you that.

Electrical and gas: where DIY should stop

Wiring in a new circuit for a hood that didn't have one before, or moving the hood's position so the existing wiring doesn't reach, is where I'd personally stop and call an electrician, and I say that as someone who's happy to DIY most things. In many places it's also a legal requirement for new circuits to be signed off by a certified electrician, and insurance can be affected if unpermitted electrical work causes a fire. The cost of a qualified electrician for a single new circuit is small compared to the cost of getting it wrong, and it's the one part of this job where cutting corners isn't a time-saving shortcut, it's a genuine risk.

If you're installing over a gas range and the hood sits above anything involving a gas line modification, that's a job for a licensed gas fitter, full stop. Range hood manufacturers specify minimum mounting heights above gas cooktops (commonly 30 inches, sometimes less for certain models, check your specific manual) precisely because of heat and flare-up risk, and mounting too low is a fire hazard regardless of how level and solid the bracket is.

A worked example: the island hood that nearly didn't happen

Say you're renovating a kitchen and want a 36-inch canopy hood hanging over a new island, with no existing duct anywhere near it. On paper the hood install looks like step seven of the kitchen plan. In reality, routing a duct from an island location to an exterior wall or roof often means going up through ceiling joists, through an attic space, and out through the roof with a real roof cap, or horizontally through a wall with multiple elbow joints that each cut into your effective CFM. That run could easily be 20 to 25 feet with three bends, which pushes you toward needing a larger duct diameter (8-inch instead of 6-inch) just to keep the airflow usable, which in turn means a bigger roof penetration and possibly structural work around joists.

None of that is a DIY weekend job. It's the kind of project where a homeowner buys a beautiful hood, gets as far as realising the duct run is the hard 80% of the job, and either pays a contractor to finish it or settles for a recirculating (non-vented) version that filters air through charcoal and pushes it back into the room instead of outside. Recirculating hoods work fine for light cooking but they don't remove heat, humidity, or most odours the way a vented hood does, and if you're a serious cook, that trade-off matters more than most buying guides let on.

Common mistakes that make a finished install underperform

• Mounting the hood too high "to be safe" above the cooktop, which drops capture efficiency significantly. Stick to the manufacturer's specified height, usually 24 to 30 inches above an electric cooktop and higher above gas.
• Using cloth duct tape instead of foil tape or mastic sealant, which dries out and peels within a year or two from heat exposure.
• Skipping the make-up air consideration on very high-CFM hoods (typically above 400 CFM), which in a tightly sealed modern home can cause the hood to struggle to pull air, or in worse cases backdraft a gas water heater or furnace. This is a real building code issue in many areas, not a theoretical one.
• Not weighing the hood and getting a second person before lifting it into place, which is how brackets get bent and backs get hurt.
• Buying on CFM rating alone and ignoring noise rating (measured in sones). A 600 CFM hood running at 8 sones is loud enough that people turn it off halfway through cooking, which defeats the entire purpose.

When to just hire someone

If your job involves any of these, it's worth getting quotes rather than pushing through solo: new electrical circuit, duct run longer than about 15 feet or with more than two bends, roof or exterior wall penetration, gas line work, or a hood heavier than you and a helper are comfortable lifting safely. A like-for-like swap with matching duct and wiring is a legitimate DIY job for most people with basic tools and patience. Everything past that is a renovation project wearing a range hood as a disguise.

Frequently asked questions

How long does a DIY range hood installation take?

A like-for-like swap with matching duct and wiring typically takes half a day to a full day. A new ducted install with wall or roof penetration and a new electrical circuit is realistically a multi-day project and often needs professional help for the electrical and ducting portions.

What size duct do I need for a range hood?

Most residential hoods use a 6-inch round duct (handles up to roughly 400 CFM in practice) or a 3.25 x 10 inch rectangular duct. Match the duct size to your hood's CFM rating and factor in length and bends, since every bend and extra foot reduces effective airflow.

Can I install a range hood without professional help?

If you're replacing an existing hood in the same spot using the existing duct and wiring, yes, most people can do this themselves with basic tools. If you need a new electrical circuit, new ductwork through a wall or roof, or any gas line work, hire a licensed electrician or gas fitter for that specific portion.

Why is my new range hood not pulling air well?

The most common cause is an undersized or overly long duct run with too many bends, which restricts airflow regardless of the hood's rated CFM. Unsealed duct joints, a hood mounted too high above the cooktop, or a mismatch between duct size and the hood's outlet can all cause the same problem.