Cooker Hood Installation near you

The hood you choose changes the number the kitchen has to hit. In Approved Document F Volume 1, the statutory guidance for dwellings in England, an intermittently operated kitchen extract must reach 30 litres per second when a cooker hood extracts to the outside, and 60 litres per second when there is no hood or the hood does not extract outside. That is the whole argument for ducting in one line: a hood that vents outdoors halves what the kitchen's extract has to achieve, and lets a single appliance do the job that would otherwise need a much larger fan somewhere else in the room.

There are two details attached to those figures that installers routinely miss. The diagram accompanying the 30 litres per second case carries a note that the cooker hood should span at least the full width of the cooker, which rules out a slim hood over a wide range. And where a cooker hood is used to extract to the outside, the height of the hood above the hob surface should be either as specified in the manufacturer's instructions or, if no specification is available, between 650 and 750 millimetres. Extract terminals and fans generally should sit as high as practicable and a maximum of 400 millimetres below the ceiling, but the document exempts cooker hoods from that rule, because they are positioned by the hob instead.

Continuous systems are measured differently: for a kitchen the high rate is 13 litres per second, with the continuous rate set by the whole dwelling ventilation requirement rather than the room. Approved Documents are guidance for England; Wales, Scotland and Northern Ireland publish their own equivalents, so confirm the standard that applies where you live before specifying anything.

A hood is only as good as the hole it breathes through, and Approved Document F sets out how that hole should be built. Rigid ducts should be used wherever possible. Flexible ductwork, where it is installed at all, should be used only for final connections, should be a maximum of 1.5 metres in length, and should meet the relevant BSRIA standard. Any flexible duct should be installed so the full internal diameter is maintained and flow resistance is minimised, which means pulling it taut and making sure it does not pass through an opening narrower than the duct itself.

This is the interaction that turns a simple hood installation into a job for a gas engineer. Approved Document J explains that extract fans lower the pressure in a building, which can cause the spillage of combustion products from open-flued appliances, and that this can occur even if the appliance and the fan are in different rooms. Ceiling fans produce air currents and local depressurisation that can do the same. In buildings where open-flued combustion appliances and extract fans are both installed, the appliances should be able to operate safely whether or not the fans are running.

The limits it gives are specific. For gas appliances, where a kitchen contains an open-flued appliance, the extract rate of the kitchen extract fan should not exceed 20 litres per second, which it also expresses as 72 cubic metres per hour. For oil appliances the limit is 40 litres per second with a pressure jet burner and 20 with a vaporising burner. For solid fuel appliances the advice is to avoid installing extract ventilation in the same room at all, and to seek specialist advice if mechanical extraction is unavoidable.

Read that alongside Approved Document F's 30 litres per second for a ducted hood and the tension is obvious, which is exactly why the guidance also requires testing. A suitable test is to check for spillage when appliances are subjected to the greatest possible depressurisation, with all external doors, windows and adjustable ventilators closed, and several tests may be needed including one with the door to the appliance room closed and all fans in that room on maximum. Approved Document J notes that less obvious fans count too, including those inside domestic appliances such as tumble dryers.

Replacing a hood in an existing kitchen is treated gently by the rules. Approved Document F states that if an extractor fan or cooker hood is replaced and it uses the existing cabling, this does not need to be notified to a building control body. Approved Document P reaches the same conclusion by a different route: only installing a new circuit, replacing a consumer unit, or altering existing circuits in a special location are notifiable, and a kitchen is not a special location. A new switched fused connection unit for a hood, spurred from an existing circuit, is therefore not notifiable, though it must still be installed and tested to BS 7671.

Refurbishment brings its own rule. Approved Document F says that where building work is carried out in a kitchen or bathroom, any existing fans, including cooker hoods where they extract to the outside, should be retained or replaced, and appropriate checks should be made to determine whether any retained ventilation devices are working correctly. If there was no ventilation system in the original room it is not necessary to provide one, but additional ventilation may be necessary if the refurbishment is likely to make the building less compliant with the ventilation requirements than it was before. The document also carries a note that if a combustion appliance is installed in a kitchen where building work is carried out, Part J must be considered.

The honest comparison is not about performance, it is about where the moisture and the grease end up. A ducted hood removes water vapour, cooking odours and grease-laden air from the building. A recirculating hood traps grease in a metal filter and odour in a charcoal cartridge and returns warm, moist air to the kitchen. In a well-insulated modern flat that moisture has nowhere to go and finds the coldest surface in the room, which is how a hood becomes a condensation problem.

Ask each installer the same three questions and the quotes become comparable: where will the duct run and what will it be made of, what extract rate will the finished system achieve and how will that be demonstrated, and whether anything in the house burns gas or oil on an open flue. A good answer to the first involves rigid duct and a short route. A good answer to the second involves a measurement rather than the figure printed on the hood's box, since a manufacturer's free-air rating is not what a hood delivers at the end of a real duct.

LokalMatch is how you reach those installers. You describe the kitchen, the hob position, the wall construction and what you want the hood to do once, and firms covering your postcode contact you directly. They pay for the requests they receive, and describing the job costs you nothing. LokalMatch does not do installations, does not set or approve prices, and does not vet, rank or recommend the businesses that reply, so checking electrical scheme membership, and bringing in a Gas Safe registered engineer where an open-flued appliance is in the picture, remains yours to arrange.