How To Fit A Cooker Hood

Knowing how to fit a cooker hood properly matters for more than appearance. A correctly installed hood removes steam, grease, odours and airborne moisture at the point of cooking. A poor installation can be noisy, ineffective, difficult to clean and, in some cases, unsafe around gas appliances or electrical connections.

Most capable DIYers can fit a simple recirculating cooker hood, particularly where the electrical connection and cabinet layout already exist. A ducted hood that vents outside usually needs more planning. Drilling through an external wall, routing rigid ducting, managing electrical connections and preserving the kitchen’s fire and ventilation performance can turn a small job into a half day or full day project.

This guide explains how UK homeowners can plan and fit a cooker hood, decide between extraction and recirculation, understand the rules, avoid common fitting mistakes and know when to call a qualified electrician, kitchen fitter or ventilation specialist.

Choose the right type of cooker hood before fitting

There are two main ways a cooker hood works. An extraction hood removes air from the kitchen through ducting and discharges it outside. A recirculating hood draws air through grease and carbon filters before releasing it back into the room.

Extraction is normally the better option. It removes moisture and cooking pollutants from the building rather than attempting to filter them. This is particularly useful in kitchens with frequent cooking, poor natural ventilation, condensation on windows or an open plan layout.

Recirculating hoods are useful where external ducting is impractical, such as a flat with restrictions on external alterations, a kitchen positioned away from an outside wall, or a property where the route through cupboards would be excessively long. They are less effective at controlling humidity because they do not remove steam from the room.

Type of hood	How it works	Best suited to	Points to consider
Ducted extraction hood	Moves kitchen air outside through ducting	Most houses, regular cooking, kitchens with condensation issues	Needs a route to an external wall or roof outlet, works best with short rigid ducting
Recirculating hood	Filters air and returns it to the kitchen	Flats, internal kitchens and restricted properties	Needs carbon filters, does not remove moisture, filters need regular replacement
Chimney hood	Wall mounted canopy with a vertical chimney section	Hobs on an outside wall or wall with cupboard clearance	Usually requires accurate height setting and solid wall fixings
Integrated hood	Fitted inside a wall cabinet	Concealed kitchen designs	Cabinet needs correct internal dimensions and ventilation openings if specified
Canopy hood	Built into a purpose made housing or chimney breast	Bespoke kitchens and island features	Often needs more joinery work, access panels and careful duct planning
Island hood	Suspended above an island hob	Kitchen islands with suitable ceiling structure	Heavier fitting, ducting is more difficult, ceiling support must be verified

Before ordering a hood, check its width, depth, extraction rate, mounting method and duct size. The hood should normally be at least as wide as the hob. A 600mm hood suits a standard 600mm hob. A 900mm hood generally performs better over a 900mm range cooker because it captures more of the rising cooking plume.

For help selecting an appropriate unit and understanding air movement in kitchens, read Choosing the Right Extractor Fan for Bathrooms and Kitchens Explained.

UK ventilation requirements for cooker hoods

A cooker hood is not always a substitute for the kitchen ventilation required by Building Regulations. In a new kitchen, an extension, a major refurbishment or a newly created kitchen, ventilation should be considered against Approved Document F, which covers ventilation in dwellings.

Approved Document F gives a typical intermittent extract rate of 30 litres per second for an extract fan located above a hob, or 60 litres per second if the extract point is elsewhere in the kitchen. Continuous systems have different requirements. A recirculating cooker hood does not provide external extract ventilation because it returns air to the room.

The current guidance can be found in the government publication Approved Document F, ventilation. Building Control may expect an appropriate extract system where substantial work is being carried out, especially if an existing external fan is being removed during a kitchen refit.

In an existing kitchen where you are simply replacing one hood with another, Building Regulations approval is not usually needed solely because a new hood is fitted. However, the installation should not make the home’s existing ventilation worse. Removing a ducted fan and replacing it with a recirculating hood may be a backward step in a kitchen already affected by moisture or mould.

Planning permission is not normally required for a modest external vent terminal on a typical house. Listed buildings, flats, conservation areas, leasehold properties and properties subject to restrictive planning conditions need more care. A listed building may require listed building consent even for seemingly minor external changes. The government’s guidance on when planning permission is required is a useful starting point, but the local planning authority should be consulted where there is any uncertainty.

For a fuller explanation of duct sizing, condensation control and ventilation rates, see Ventilation in UK Bathrooms and Kitchens Explained Extractor Fan Sizing Ducting Rules and Condensation Control.

Measure the position and installation height

The most common reason a hood fits badly is that measurements were taken from the worktop rather than from the hob surface. Always measure from the top of the pan supports or the ceramic, induction or electric hob surface, because this is the reference point used in manufacturer instructions.

Many cooker hood manufacturers specify a minimum clearance of around 650mm above an electric or induction hob and around 750mm above a gas hob. Some models require more clearance. The hob manufacturer may also state a minimum clearance to combustible surfaces, cupboards or extractor hoods. The greater requirement should be followed.

Do not assume that a hood can be installed lower because it looks better. A hood mounted too low is exposed to excessive heat, can obstruct cooking and may invalidate the manufacturer warranty. A hood mounted too high may fail to capture steam effectively, particularly on front rings of the hob.

Check these dimensions before drilling:

• The width of the hob and the width of the hood.
• The minimum and maximum installation height in the hood instructions.
• The distance to wall cupboards, splashbacks and tall units.
• The depth of the hood, especially where a cupboard door opens nearby.
• The route of any duct behind or above the hood.
• The position of the electrical supply and isolation point.
• The location of gas pipes, water pipes and electrical cables.
• The hood’s weight and the structure available for fixings.

For an integrated hood, check the cabinet manufacturer’s instructions as well as the hood instructions. Some units require a specific cabinet width, ventilation openings in the cabinet, a cut out for ducting, or a void above the hood for air circulation. Do not simply screw a hood into the thinnest part of an ordinary flat pack cabinet without checking whether it can carry the weight.

Plan the duct route for an extraction cooker hood

A powerful hood cannot perform properly if the ducting is undersized, excessively long or crushed behind kitchen units. This is one of the most frequent problems found after kitchen installations.

Use the duct diameter specified by the hood manufacturer. Many domestic hoods are designed for 150mm ducting. Reducing a 150mm outlet to 100mm duct may make the installation easier, but it reduces airflow and increases noise. A reduction can make a premium hood perform no better than a much cheaper model.

Rigid smooth bore ducting is generally best. Round rigid duct is efficient and easy to seal. Rectangular duct can be useful inside cupboards or ceiling voids, but its equivalent capacity must be suitable. Flexible foil duct should be a last resort. Its ribbed internal surface creates resistance, gathers grease and can become crushed.

Keep the route short and as straight as practical. Every sharp bend increases resistance. Two gradual bends are better than several tight elbows. Avoid running the ducting into an unventilated loft space. Steam discharged into a loft can create condensation, mould, wet insulation and timber decay.

The external terminal should be weatherproof, fitted securely and positioned so expelled air will not immediately re enter an opening window, trickle vent or air intake. Use an external grille or cowl appropriate for kitchen extraction, ideally with a backdraught shutter. The shutter helps limit cold air entering the kitchen when the hood is off.

If ducting passes through a cupboard, cut the opening neatly and protect exposed cabinet edges where possible. If it passes through an external wall, the hole should slope slightly downwards towards the outside. This helps any condensation drain outward rather than back into the duct and kitchen.

Drilling through an external wall

Core drilling a 125mm or 152mm opening through brickwork is not a casual job. It requires a suitable diamond core bit, a powerful drill, dust control, safe access outside and care around concealed services. On a cavity wall, the duct should bridge the cavity cleanly without leaving a route for water penetration.

Before drilling, inspect both sides of the wall. Check for external sockets, gas meter boxes, boiler flues, drainpipes, air bricks and cables. Indoors, use a reliable cable and pipe detector, but never trust a detector as the only check. Consider the likely route of services from sockets, switches, radiators and plumbing fixtures.

A kitchen fitter or ventilation engineer will commonly charge around £150 to £350 to core drill and fit a basic external vent, depending on wall thickness, access and whether ducting is included. Scaffold access, stone walls, tiled surfaces or awkward high level locations can increase the cost considerably.

Electrical requirements when fitting a cooker hood

Most cooker hoods are supplied with either a moulded plug or a flex intended for connection to a switched fused connection unit. The manufacturer instructions must be followed. Many hoods use a 3 amp fuse, although the correct fuse rating is determined by the appliance instructions and cable size.

The hood should have accessible means of isolation. In practice, this is often a switched fused connection unit above a wall cabinet or inside an adjacent cupboard, with the hood flex connected through a flex outlet plate. A socket hidden directly behind a chimney hood may be inaccessible after installation, which is inconvenient for maintenance and may not meet the manufacturer’s access requirements.

Turn off the relevant circuit at the consumer unit and verify that it is dead before any electrical work. Do not rely only on the wall switch. Proper safe isolation requires suitable test equipment and competency.

Minor work on an existing circuit in a kitchen is not automatically notifiable under Part P. However, installing a new circuit, altering a consumer unit or carrying out work in a special location can involve notification requirements. Electrical work must comply with BS 7671, commonly known as the IET Wiring Regulations. A registered electrician can test the work and issue the appropriate paperwork.

If you are uncertain about the supply, cable route, earthing arrangement or whether a connection point is suitable, use an electrician registered with a competent person scheme. Homeowners can also read Part P Explained for Homeowners Electrical Work Rules Certificates and Common Mistakes before authorising kitchen electrical work.

How to fit a cooker hood step by step

Always read the model specific instructions before starting. Mounting brackets, fixing centres, chimney sections, duct adaptors and electrical arrangements vary widely between manufacturers.

1. Confirm the installation type. Set the hood for extraction or recirculation as required. Some hoods need an internal blanking plate, directional flap or carbon filter fitted before they are mounted.
2. Isolate the electrical supply. Switch off the correct circuit at the consumer unit. Verify dead before touching a fixed electrical connection.
3. Mark the centre line. Find the centre of the hob and transfer this line vertically onto the wall. The hood should sit centrally over the hob, not simply centrally between cupboards.
4. Mark the height. Measure from the hob surface and mark the required underside height. Confirm this against both appliance manuals.
5. Locate services and structure. Check for cables and pipes. Determine whether the wall is solid brick, blockwork, plasterboard on studs or a chimney breast with voids.
6. Fit the mounting bracket. Use the bracket template or dimensions supplied. Fix into sound masonry, studs or suitable structural noggins. Standard plasterboard fixings are rarely enough for a heavy chimney hood.
7. Form the duct opening. If extracting outside, drill the wall opening or prepare the cabinet and ceiling route. Fit the external vent and seal around it with suitable exterior sealant.
8. Fit ducting. Connect duct sections securely. Keep them supported and as straight as possible. Seal joints with appropriate foil tape or duct seals. Do not use ordinary cloth tape, which fails with heat and grease.
9. Mount the hood. Lift the hood carefully, ideally with a second person. Engage it on the bracket, secure all safety screws and check it is level.
10. Make the electrical connection. Connect only in accordance with the manufacturer instructions. Ensure the hood flex is not trapped, stretched or resting against hot surfaces.
11. Fit chimney covers or cabinet panels. Secure decorative sections without crushing ducting or blocking intended air paths.
12. Test the hood. Restore power, test every fan speed and light, then check airflow outside. Listen for rattles, vibration and backdraught flap noise.

A straightforward replacement hood may take two to four hours for an experienced installer. A new ducted installation through an external wall often takes four to eight hours. Island hoods, difficult duct routes, stone walls and bespoke cabinetry can take a full day or longer.

Typical cooker hood fitting costs in the UK

Prices vary by region, access and kitchen layout. London and the South East are often higher. The figures below are realistic working ranges for labour and standard materials, excluding major electrical upgrades or structural alterations.

• Basic recirculating hood replacement: £100 to £220.
• Integrated hood replacement: £150 to £300, depending on cabinet alterations.
• Wall mounted chimney hood with existing duct and power point: £180 to £350.
• New duct route through an external wall: £350 to £750, including basic core drilling, ducting and external grille.
• Electrician to provide or alter a local connection point: £120 to £300 for straightforward work.
• Island hood installation: £450 to £1,000 or more, particularly where ceiling reinforcement and concealed ducting are needed.
• Carbon filters for recirculating hoods: £15 to £70 per set, usually replaced every three to six months depending on cooking habits.
• Rigid ducting and fittings: £40 to £180 for a simple route.
• Cooker hood supply cost: £80 to £1,500 or more, depending on size, brand, airflow rate, finish and controls.

Ask for a written quote that confirms whether it includes removal of the old hood, making good around the duct opening, electrical testing, carbon filters, external grille, ducting, cabinet alterations and waste disposal. These details often cause disagreement where a low headline price has been accepted without a full scope of works.

Common mistakes to avoid when fitting a cooker hood

Using undersized ducting

Reducing a 150mm outlet to 100mm ducting is one of the biggest performance killers. The hood will sound louder, extract less effectively and may leave grease deposits on cupboards. Follow the manufacturer duct size wherever possible.

Using long lengths of flexible duct

Flexible duct is convenient but rarely performs well. It sags, traps grease and restricts airflow. Use rigid duct for the main route and keep any flexible connector short, straight and fully extended if one is unavoidable.

Fitting the hood too high or too low

A hood outside the specified height range can be ineffective or unsafe. Check both the hob and hood instructions before mounting. Do not use internet measurements as a substitute for the product manuals.

Fixing into weak plasterboard

Some chimney hoods weigh 15kg to 30kg before ductwork is connected. A heavy unit fixed only to plasterboard can loosen, crack the wall finish or fall. Locate studs, install timber noggins where practical, or use suitable fixings into masonry.

Ignoring the need for replacement air

An extractor cannot remove air efficiently if the kitchen is sealed tight. In normal use, a trickle vent, open internal route or slightly open window may help make up air reach the room. This is particularly relevant for powerful hoods in well insulated homes.

Installing close to an open flued gas appliance

Powerful extract systems can affect combustion air and flue operation in some circumstances. If the kitchen contains an older open flued gas boiler, gas fire or similar appliance, seek advice from a Gas Safe registered engineer before increasing extraction. The engineer can assess whether the appliance and ventilation arrangement remain safe.

Leaving the filters unmaintained

Grease filters clogged with fat reduce airflow and create a fire risk. Metal filters are commonly dishwasher safe, but check the manufacturer instructions because some finishes can discolour. Carbon filters cannot normally be washed unless the manufacturer specifically says they are washable.

For practical cleaning guidance, including filter care and degreasing methods, see How To Clean A Cooker Hood.

Testing the cooker hood after installation

Do not judge a hood only by the sound of the motor. Test whether it is actually moving air. Hold a sheet of kitchen paper near the grease filter on a low setting. It should be drawn towards the filter, although it should not be left there unattended.

For an externally ducted hood, check the external grille while the fan runs. You should feel a clear discharge of air. Inspect the duct route inside cupboards for air leaks, loose joints or vibration. If the hood rattles, first check the mounting screws, duct connection, backdraught flap and chimney cover panels.

Steam from a pan of water provides a useful real world check. The hood should capture most steam from the rear rings at its normal cooking speed. Some steam escaping from front pans is normal, especially where the hood is mounted high, but heavy condensation on nearby windows suggests that airflow or kitchen ventilation needs attention.

FAQ

Can I fit a cooker hood myself?

You can usually fit a basic recirculating hood yourself if you are competent with measuring, drilling, using suitable wall fixings and following the manufacturer instructions. Electrical work should be limited to tasks you are genuinely competent to carry out safely. If a new electrical supply, fused connection unit or circuit is needed, employ a qualified electrician.

A ducted installation is more involved because it may require core drilling through an external wall, weatherproofing, duct sealing and careful routing around kitchen units. Many homeowners choose a kitchen fitter for the mechanical work and an electrician for the final connection.

Does a cooker hood need to vent outside?

No. Many hoods can operate in recirculation mode with carbon filters. However, external extraction is normally more effective because it removes steam, odours, grease laden air and moisture from the house. Recirculating hoods filter some odours and grease but do not remove water vapour.

For new kitchen work, a recirculating hood alone may not satisfy the extract ventilation expectations set out in Approved Document F. A separate ducted extract fan may be required.

How far above a hob should a cooker hood be fitted?

The exact distance depends on the hood and hob manufacturers. A common minimum is 650mm above electric or induction hobs and 750mm above gas hobs, but some appliances need more space. Measure from the cooking surface, not the worktop. Always follow the larger minimum clearance where the two appliance manuals differ.

Do cooker hoods need a dedicated electrical circuit?

Not usually. Many domestic cooker hoods are connected to an existing kitchen circuit through a switched fused connection unit, using the fuse specified by the manufacturer. A dedicated circuit may be appropriate for some larger installations or where the existing circuit has capacity issues, but this should be assessed by an electrician.

New circuits and consumer unit changes are more tightly controlled under Part P than minor alterations to an existing circuit. Proper testing and certification are essential.

How often should cooker hood filters be cleaned or replaced?

Metal grease filters should usually be cleaned every month or two in a busy kitchen. Households that fry regularly may need to clean them more often. Carbon filters in recirculating hoods commonly need replacement every three to six months, although long life filters may have different servicing intervals.

Clean filters improve extraction, reduce odours and lower the chance of grease becoming a fire hazard. Keep a note of the filter type and replacement date inside a kitchen cupboard so the task is not forgotten.

Final Thoughts

A cooker hood works best when it is correctly sized, mounted at the right height and connected to a short, adequately sized duct route. Spend time planning the outlet position, electrical isolation point and wall fixings before buying the appliance. Correct installation prevents the usual complaints, poor extraction, excessive noise, condensation and awkward maintenance.

If your project involves new ducting, electrical alterations, an island hood, a difficult external wall or any concern about gas appliances, get professional help. You can post a job on BookaBuilderUK to get free quotes from vetted local tradespeople.