Skip to main content

Cooker Hoods: What to Consider

Island mounted cooker hood
The Miele DA6890 is a downdraft cooker hood that is concealed within an island unit. The canopy rises 400mm over the worktop and can achieve an extraction rate of up to 725m3/h. It also features touch controls and dimmable LED lighting. (Image credit: Miele)

Getting the extraction right in your kitchen — usually via a cooker hood — is integral to creating a healthy and clean home. Not only does extraction remove odours, it can also take away grease and steam, making your kitchen easier to maintain and more pleasant to spend time in. Cooker hoods need to complement your hob and your kitchen layout, too — as well as fit the aesthetic of the room.

Your primary choice will be between a ducted extractor and a recirculation model: the former requires installation with a series of ductwork that takes the extracted air outside, while the latter cleans the air over a filter and returns it to the room.

Smart technology extractor cooker hood

The Hoover Wizard is a smart technology-enabled extractor hood, which can be controlled via an app in extraction or recirculation modes. It’s height adjustable (665-1,115mm), offers four speed settings and a maximum extraction rate of 707m3/h. (Image credit: Hoover)

What are Ducted Extractor Cooker Hoods?

As ducted extractors need to be connected to the outside to vent the air, there are some restrictions over where they can be installed. Remember too that ducting is not usually supplied with the extractor and you will need to buy and install this.

The path and size of your ducting will affect its extraction rate: a shorter route with fewer bends and a wider diameter of the ducting (150mm, for example) will provide optimum extraction.

What are Recirculation Cooker Hoods?

recirculation model will extract grease in the same way as a ducted model – trapping it in a grease filter – but rather than port the air externally to remove cooking smells, it purifies the air with a charcoal filter (which needs to be regularly replaced), trapping odours, before venting the cleaner air back into the room. You may also find that some steam is returned to the room via this method too.

In general, recirculation models offer a reduced extraction rate at a higher noise level than ducted models — it is usually more efficient to port the extracted air directly outside than to filter it inside the unit.

Does a Cooker Hood need Ducting?

You should be aware that most cooker hoods are not supplied with ducting — however, this is essential if you are opting for an extraction model. Ducting can usually be sourced from the supplier, but most DIY shops also sell kits.

For the best airflow, choose one with a 150mm diameter as opposed to 120mm, and opt for rigid ducting over flexible. The ridges in flexible ducting can slightly restrict the airflow. If investing in a downdraught extractor (one that rises from the worktop), ducting will run under the flooring or along the back of the units.

Angled extractor cooker hood

The CDA EXA60 is a 600mm angled extractor with touch control, a timer and a filter warning. It has an extraction rate of 610m3/h with a noise level of 62dB. It’s available in black and silver, back or top vented and fitted as a ducted unit or to recirculate. (Image credit: CDA)

How Wide should my Cooker Hood be?

If your hob measures up to 750mm wide, a cooker hood width of 900mm is advised, and if it measures up to 900mm wide, a width of 1,200mm is best. Hobs fall into two categories: ‘cold’, where the heat is generated in the pan, such as induction hobs, and ‘hot’, with a high-temperature flame, such as gas hobs. A cold hob works best with a hood that is wider than the hob, as the vapours disperse over a wider area.

What is an Extraction Rate?

All cooker hoods have an extraction rate, and you must opt for a hood that allows for 12 changes of air per hour. To calculate this, work out the volume of the kitchen in cubic metres then multiply it by 12.

For example, if a kitchen is 5m long, 3m wide and 2.5m high, multiply length by width by height to find the cubic capacity (which in this case is 37.5m3). The extraction rate would therefore be 12 x 37.5m3, which is 450m3.What Height Should I Install a Cooker Hood Above the Hob?

Angled chimney cooker hood

The Smeg KFAB75 is a retro-styled angled chimney hood that is available in four colours: cream, white, black and red. It offers an A+ energy rating, electronic controls and a maximum extraction rate of 797m3/h with a maximum noise level of 72dB. (Image credit: SMEG)

What Height Should I Install a Cooker Hood Above the Hob?

Your hood should be placed at the recommended distance of between 650mm (for electric) or 750mm (for gas) above your hob. Do check your ceiling height. Although most wall-mounted chimney hoods and island hoods are adjustable, this is not always sufficient — and remember, standard cooker hoods will not work over kitchen islands.

What Cooker Hoods Work Best Over a Kitchen Island?

If you have a hob in a kitchen island you will need to specify a special extractor for this. “Where the extractor hood could once prove tricky when planning an island unit, the variety now available means you can opt to make it a feature in its own right or keep it as a discrete addition that doesn’t detract from the overall look,” says Tori Summers of Benchmarx.

You could also opt for a downdraft extractor, which can be installed into your island, or choose an integrated unit, says Tori: “If you are using the island to incorporate a hob or sink area look out for the latest hobs that incorporate extractor fans as these do away with the need for an overhead extractor.”