DIY GUIDE · ELECTRICAL · CHECKED OCTOBER 2026
How to replace a kitchen extractor fan yourself
An afternoon. €74–€95 for a kitchen fan, an outside grille and a voltage tester.
Same size, same hole, same supply, kitchen or utility only. Isolate, prove dead, swap, seal and test — and leave bathroom fans to a registered contractor.
- Every step, start to finish
- Checked October 2026 — sources at the end
- Honest about when to call a pro
FIRST, THE HONEST ANSWER
Do it yourself, or get a fitter?
Do it yourself if…
- The fan is in a kitchen or utility room, not a bathroom, shower room or toilet
- The new fan is the same size and type as the old one and fits the same hole and wall sleeve
- The fan's supply comes from a switch or isolator you can turn off, and you can switch off its circuit at the board
- You can reach the fan safely, from a stepladder, with both hands free
Get a pro if…
- The fan is in a bathroom, shower room or en-suite
- A new hole has to be cut through the wall or window, or the fan is being moved
- There is no isolator and a new switch or supply is needed
- There is an open-flued boiler, stove or open fire in the same room and you are not sure about the air supply
Safety first
- Isolate at the board and prove the fan's terminals dead with a tester you have proved on a live circuit before and after. The HSA's electricity guidance sets out exactly this check.
- On the stepladder, keep three points of contact and do not stand on the top two steps unless there is a handrail, as the HSA's ladder guidance says. Outside, have someone foot the ladder.
- The fan maker we read asks for a local isolator that disconnects all poles with a contact gap of at least 3mm, and says wiring should be done by a suitably qualified person. If you are not confident with the connections, have a Registered Electrical Contractor make them.
- A fan can pull fumes back down the flue of an open-flued boiler, stove or open fire in the same room. Check for spillage, keep vents open and keep a carbon monoxide alarm in the room.
- Never replace a fan in a bathroom, shower room or en-suite yourself; that is restricted electrical work in Irish law.
Stop here: Stop here: bathrooms, new supplies and fuel-burning appliances
Under Irish law, S.I. No. 264 of 2013, the modification, installation or replacement of an electrical installation in a special location such as a bathroom or shower room is restricted electrical work that only a Registered Electrical Contractor may carry out and certify, so a bathroom fan swap is not a DIY job; the CRU prosecutes unregistered restricted work. A new circuit or a new supply to a fan is restricted too. If a fan affects a gas appliance's flue, the appliance must be checked by a Registered Gas Installer, and the danger of carbon monoxide spillage means you should not run the fan until it has been. How to hire an extractor fan installer →
| MATERIAL | COVERAGE | FOR THIS JOB |
|---|---|---|
| Replacement extractor fan | Same size and type, meeting the room's extract rate, with the same control type | One |
| Outside grille or cowl | To match the duct size, with a fly screen | One, if the old one is broken |
| Exterior sealant | To seal the outside grille to the wall | One tube |
| Wall plugs and screws | Usually supplied; suited to the wall | One set |
Does the fan meet the extract rate
36 m² of wall → 20 L for 2 coats. Buy about 20 L.
Fan check: the fan's rated flow in litres a second must be at least the room's minimum. A kitchen fan away from the cooker needs 60; a fan rated at 220 cubic metres an hour gives about 61 litres a second, because 220 ÷ 3.6 is 61.
Boxes often show the flow in cubic metres an hour. Divide by 3.6 to get litres a second, and compare it with the rate the guidance gives for your room.
Ireland's ventilation guidance, Technical Guidance Document F, gives minimum intermittent extract rates: 60 litres a second for a kitchen fan in general, 30 litres a second if it is immediately next to the cooker, and 30 litres a second for a utility room. Check the new fan's rated flow on its box. A fan that cannot meet the rate leaves steam and condensation behind.
Measure the old fan's spigot and the hole through the wall or glass. The maker of one common kitchen fan we read cuts a 152mm hole and says its fan will suit existing holes up to 185mm. A new fan that needs a bigger hole is not like for like.
An axial fan suits a short duct straight through the wall. A centrifugal fan pushes against longer ducts and bends. The ventilation guidance says axial fans are normally suitable only for short through-the-wall ducts of the fan's own size. Replace like with like unless you are changing the ducting, which is new work.
Fans come plain, with a pull cord, a timer, or a humidity sensor. A timer or humidity fan often needs an extra switched live core that a plain fan's supply does not have. Buy the type your existing wiring supports; changing the control is not like for like.
The kitchen fan maker we read rules out grease-laden air, corrosive or flammable vapours, anywhere in reach of a shower or bath, and rooms below 5°C or above 40°C. It also warns that when a fan removes air from a room with a fuel-burning appliance, the replacement air must be enough for both.
THE PART THAT DECIDES THE FINISH
Before you start — where the fan is and how it is fed
Look at the fan and its supply, and match it to one of these. Do its prep first.
Wall fan through a sleeve
A fan on the inside wall with a duct through to a grille outside.
- Find the fan's isolator switch, often a small switch near the ceiling or beside the fan
- Find the circuit at the board as well; an isolator alone is not enough
- Look outside at the grille for damage, birds' nests or a stuck flap
- Check the duct is clear and slopes slightly down to the outside
Window fan
A fan fitted through a hole in a pane of glass.
- Plan to remove the fan from the inside and outside without stressing the glass
- Have a helper outside to hold the outer grille as you release it
- Check the new fan's window kit suits your glass thickness
- If the glass is cracked near the hole, stop and call a glazier
Fan above or near a cooker
A wall fan close to the hob, often clogged with grease.
- Clean grease from the wall and the old fan's surround before removing it
- Check the new fan is suitable for kitchen use near cooking
- Keep the fan clear of the hob's flames or heat
- If a cooker hood is involved, this guide does not cover it
Room with a boiler, stove or open fire
A fuel-burning appliance shares the room with the fan.
- Check whether the appliance is room-sealed; if it is open-flued, a fan can pull fumes back down its flue
- Look for a permanent air vent in the room and make sure it is open
- If you are not sure, ask the appliance's service engineer before fitting a more powerful fan
- Fit a carbon monoxide alarm in the room if there is not one
THE JOB
How to replace the fan
Isolate and prove dead
15 minSwitch the fan off at its isolator, then switch off its circuit at the board, tape over the breaker and leave a note. Set up the stepladder. Remove the fan's indoor grille, then test the terminals with your voltage tester, having first proved the tester on a live socket. Prove the tester again afterwards.
- Turn the fan on first so you can see it stop when you switch off at the board
- Keep a head torch on
- Test every terminal, including any switched live for a timer
Mistake to avoid: Relying on the fan's isolator alone. Some isolators switch only one pole, and a fan can still be live at its terminals.
Do the prep for your fan
15 minThis is the prep from the cards above. Photograph the fan's wiring, clean grease off the area, check the outside grille and duct, and check the air supply if a fuel-burning appliance shares the room.
- Label each core with tape before you release it
- Note which core went to which terminal on the old fan
- Clear the outside grille of nests and debris
Mistake to avoid: Not photographing the wiring. Timer and humidity fans have three cores and an earth, and the order matters.
Remove the old fan
20 minRelease the cores from the old fan's terminal block. Undo its fixings and ease the fan out of its sleeve or window. Cut through any old sealant round the outside grille with a utility knife and remove it from outside.
- Have someone outside to catch the outer grille
- Keep the sleeve in the wall if the new fan fits it
- Bag the old fan for recycling
Mistake to avoid: Pulling the fan out with the cable still connected. The cable is stretched inside the wall and may be damaged.
Check the hole and the duct
15 minLook at the wall sleeve: it should be sound and slope slightly down to the outside, so condensation drains away, as the fan maker asks. Clean it out. Check the new fan's spigot slides into it snugly.
- Wipe out grease and dust from the sleeve
- Check there is no gap round the sleeve inside the wall
- Measure the new fan's spigot against the sleeve before going further
Mistake to avoid: Fitting a fan to a sleeve that slopes inwards. Condensation runs back into the fan and down the kitchen wall.
Fix the new fan
20 minFeed the cable through the new fan's grommet, slide the fan into the sleeve and fix it to the wall with the screws supplied, using the old holes if they line up. Check the fan blade spins freely by hand once it is fixed.
- Keep the grommet in place so the cable is protected
- Fix the fan level; a tilted fan rattles
- If new holes are needed, scan the wall for cables first
Mistake to avoid: Overtightening the fixings and distorting the fan housing. The blade then catches the housing and the fan rattles.
Connect the supply
15 minFollowing your photograph and the fan's own wiring diagram, connect the live, neutral and earth, and any switched live for a timer or humidity control. Tighten each terminal firmly and tug each core. Fold the cable back neatly so it cannot touch the blade.
- Use the fan's own diagram; terminal markings vary between makers
- No copper should show outside a terminal
- If the old fan had an earth and the new one is double-insulated, sleeve and terminate the earth safely
Mistake to avoid: Connecting a timer fan to a supply with no switched live. It either runs all the time or never, and the timer does nothing.
Fit the outside grille and seal
20 minFrom outside, fit the new grille or cowl over the duct with its louvres pointing down, so rain cannot drive in. Run a bead of exterior sealant round its edge, leaving a small gap at the bottom for any water to escape.
- Work from a stable ladder outside, with someone footing it
- Check the grille's fly screen is in place
- Smooth the sealant in one pass
Mistake to avoid: Fitting the outside grille upside down. Rain runs straight in through the louvres and down the inside of the duct.
Switch on and test
15 minRefit the indoor grille. Remove the tape from the breaker, switch on at the board and at the isolator, and run the fan. Hold a sheet of tissue near the grille: it should be drawn firmly against it. Test any timer or humidity function.
- Check the outside grille's flaps open when the fan runs
- Listen for rattles or scraping
- Run the fan for a while and check nothing gets warm
Mistake to avoid: Assuming the fan works because it spins. If the flaps outside stay shut or the duct is blocked, it moves no air.
Check the room's appliances
15 minIf there is an open-flued boiler, stove or fire in the room, run the fan at full speed with doors and windows shut and the appliance running, and watch for smoke or fumes spilling back into the room. If you see any, switch off the fan and have the appliance engineer check the air supply.
- Do this test once with the kitchen door closed
- Make sure a carbon monoxide alarm is in the room
- Keep any permanent air vent open
Mistake to avoid: Fitting a more powerful fan in a room with an open fire or stove and never checking. It can draw fumes down the chimney into the room.
The mistakes that show
- Replacing a bathroom fan yourself
- Trusting the fan isolator without switching off at the board
- Buying a fan that falls short of the room's extract rate
- Fitting a timer fan to a supply with no switched live
- Fitting the outside grille upside down or unsealed
- Ignoring a fuel-burning appliance in the same room
Stop here and get a Registered Electrical Contractor
- The fan is in a bathroom, shower room or toilet
- A new hole, new ducting or a new position is needed
- There is no isolator, or a new switch or supply is needed
- Fumes spill from a fuel-burning appliance when the fan runs
| WHAT YOU SEE | WHY, AND THE FIX |
|---|---|
| Fan runs but moves little air | The outside flaps are stuck, the duct is blocked, or the fan is too weak for the room. Clear the grille and duct; check the fan's rated flow. |
| Fan rattles or hums | The housing is distorted by tight fixings, or the blade is catching. Loosen and refix evenly. |
| Timer does not overrun | No switched live, or it is in the wrong terminal. Switch off, prove dead and check against the diagram. |
| Water drips from the fan | The sleeve slopes inwards or the outside grille lets rain in. Correct the slope and fit the grille louvres pointing down. |
| Breaker trips when switched on | A core is touching the housing or terminals are crossed. Switch off, prove dead and recheck the wiring. |
| Smoke or fumes come back from a stove or fire when the fan runs | The fan is starving the appliance of air. Switch the fan off and have the appliance's air supply checked. |
| Condensation still forms on the windows | The fan is too small for the room, or is not run long enough. Check its rate against the guidance and run it during and after cooking. |
| Fan stopped after a few weeks | Grease build-up or a faulty motor. Clean it; if it still will not run, return it under warranty. |
WHAT YOU SAVE
What it costs to do it yourself
| Kitchen extractor fan, 150 mm | €52–€64.94 |
|---|---|
| Cowled outside grille | €9.95–€17.45 |
| Voltage tester | €11.95 |
| Total | €74–€95 |
| DIY total | €74–€95 |
Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.
The fan is most of the cost. The tester is the one tool you must have, and you keep it for the next job.
RATHER NOT?
Extractor fan installers near you, with prices shown
The ones who cover your area, nearest first, with one score from every review. No account needed to look.
Or post the job free and let them come to you.
Grease and dust slow a kitchen fan. Isolate it and wipe the grille and blade every few months; check the outside flaps move freely.
Run the fan while cooking and for a while after. Ventilation guidance treats fans as intermittent extract for when steam is produced; they only work if they are on.
An old extractor fan is electrical waste. Mywaste.ie says items like this go to a WEEE drop-off point or a civic amenity site, free of charge.
Keep the fan's instructions and wiring diagram with your house papers. The next person to work on it will need them.
Replacing a kitchen or utility extractor fan like for like: questions people ask
A kitchen or utility fan, like for like, in the same hole and on the same supply, is minor work. A bathroom fan is in a special location under the Restricted Electrical Works Regulations and must be replaced by a Registered Electrical Contractor.
Technical Guidance Document F gives 60 litres a second for a kitchen fan in general, or 30 litres a second if it is right next to the cooker. A utility room needs 30.
The outside flaps are stuck, the duct is blocked, or the fan is too weak. Clear the outside grille and duct first.
Yes. In a room with an open-flued appliance, a fan can pull fumes back down the flue. Keep air vents open, check for spillage, and keep a carbon monoxide alarm in the room.
A timer keeps the fan running after you switch off. It needs an extra switched live core; fit one only if your wiring has it.
Locufy's Irish price guide puts extractor fan installation at €150–€400 per fan, typically €250. A bathroom fan or a new hole costs more than a kitchen swap.
MORE GUIDES
More DIY guides
Sources — checked October 2026
- Vent-Axia — VA140/150 axial kitchen fans installation and wiring instructions
- gov.ie — Technical Guidance Document F, Ventilation (2019): extract rates and fans
- HSA — guide to Part 3 of the General Application Regulations 2007: electricity
- HSA — using ladders safely information sheet
- S.I. No. 264 of 2013 — Electricity Regulation Act 1999 (Restricted Electrical Works) Regulations
- CRU — RGI and Safe Electric schemes
- MyWaste.ie — electrical items
- DIY.ie — extractor fans (price check)
- Ganly's — ventilation: fans and grilles (price check)
- Ganly's — electrical accessories: voltage detector (price check)