Electrifying a commercial kitchen: supply and extraction

Taking gas out of a commercial kitchen does not remove the extraction problem. Induction hobs and electric combi ovens still produce grease-laden vapour and cooking odour, so the duct, the filtration train and the discharge point all stay. What changes is the electrical supply, which usually has to be increased, and the plant on the roof or rear elevation, which usually gets bigger. Anyone planning commercial kitchen electrification needs to deal with the connection and the plant noise before the kitchen layout is fixed.

Councils see the application as two things: a supply and plant proposal with amenity consequences, and a change to the extract system that environmental health will comment on.

What changes when gas is removed

The combustion products go, which is a real gain. No flue for the appliances, no products of combustion in the exhaust, lower NOx at the discharge point, and a simpler case on local air quality if the premises sit in an Air Quality Management Area.

What does not change:

• Grease-laden vapour from frying, grilling and searing, which still needs capture and filtration
• Cooking odour, which is produced by the food rather than by the fuel
• Duct routing, fire dampers and the discharge height above the roofline
• Fan noise, which often rises because the air volumes are similar and the plant is newer and larger

The misunderstanding that costs applicants time is assuming an all-electric kitchen can discharge at low level or through a wall grille. Odour is a function of what is cooked, and the discharge strategy follows from the menu, not the fuel.

Supply capacity and the connection

Replacing gas cooking with induction and electric ovens increases the electrical load substantially, and on a small parade of shops the existing supply often cannot carry it. The route is a connection application to the distribution network operator, which will quote for an upgraded service, a new cable, or a new transformer and substation.

Three planning consequences follow:

1. A substation or switchroom needs a location, and if it is a new external enclosure it needs to be on the application drawings
2. Cable routes may cross the public highway, which brings a street works process separate from planning
3. The lead time for a connection offer and for the works can be months, so it belongs on the programme alongside the planning application rather than after it

Where the unit is listed or in a conservation area, the switchgear enclosure and any external cable route become design issues in their own right. Internal reconfiguration to make room for a switchroom can also need listed building consent.

Extraction, odour and the abatement train

The reference document is Defra's guidance on the control of odour and noise from commercial kitchen exhaust systems, and the approach is risk based. You establish the odour risk from the cooking type, the proximity of sensitive receptors and the discharge arrangement, then specify an abatement train proportionate to that risk.

A Ventilation/Extraction Statement should set out the whole train, the air volumes, the duct route, the discharge height and the maintenance regime. Where receptors are close or the cooking is high odour, an Odour Assessment following the recognised risk based method is what environmental health will expect, and councils usually look for a suitably qualified author.

The carbon stage is where applications fail. Carbon media has a finite life, and a system submitted with carbon filters but no maintenance schedule invites a condition the operator cannot meet.

Noise from the new plant

Electrification tends to add plant: a larger extract fan, heat recovery units, additional refrigeration, and often an air source heat pump for heating and hot water. Each item has a noise rating level, and together they are assessed against the background sound level at the nearest residential facade.

The method is BS 4142:2014+A1:2019, which compares a rating level (including a penalty for tonal or impulsive character) against the measured background. A Noise Impact Assessment should cover every item of plant operating together at the worst case, not each unit in isolation, and should set out the mitigation: acoustic enclosures, attenuators, anti-vibration mounts, screening, and plant selection.

Residential flats above the unit are the hard case. Structure-borne transmission through the building frame is not addressed by an external screen, so anti-vibration isolation and duct break detailing need to be in the submitted design rather than left to the installer.

Heat recovery and the ceiling void

All-electric kitchens make heat recovery more attractive, because there is no combustion air requirement and the supply air can be tempered from the exhaust. The catch is physical. Heat recovery units, larger supply ductwork and the extract duct all compete for the same ceiling void, and in a shop unit with a low floor to floor height there is not enough of it.

Resolve that at design stage with a coordinated section through the kitchen and the void. Where the duct has to run externally up a rear elevation, say so in the application and show it, because an external riser added later is a material change that officers notice.

Conditions on hours and maintenance

Expect conditions on some or all of:

• Hours of operation of the premises and of the extract plant
• A noise limit expressed as a rating level at a defined assessment position
• Installation of the approved abatement equipment before first use
• A written maintenance and filter replacement schedule, with records kept
• A restriction on altering the system without further approval

Negotiate the maintenance condition carefully. A schedule tied to the manufacturer's recommendations and a logbook kept on site is workable. A condition requiring filter replacement at a fixed interval regardless of use is not, and operators breach it without realising.

The document pack

For a change of use or a new fit-out with external plant, the submission commonly carries:

1. Planning Statement, including the use class position and the policy case
2. Ventilation and extraction statement covering the full abatement train and the discharge point
3. Noise assessment to BS 4142 covering all plant together
4. Odour assessment where the risk is more than low
5. Air quality information where the site is in an Air Quality Management Area
6. An Energy Statement where local policy requires one for the works
7. Elevations and sections showing plant, ducts, louvres and the switchroom

If the scheme also adds charge points to the car park, the conditions that come with them are set out in electric vehicle charging in planning conditions.

PlanScope drafts the ventilation and extraction statement, the planning statement and the supporting narrative from a postcode and a short set of answers, and flags the air volumes and plant data it does not hold rather than guessing them. Enter your postcode on PlanScope to see which reports the fit-out needs.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. For specialist technical reports, qualified professional input may be required. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.