The range hood is the kitchen appliance most often chosen last, on looks alone, and it is also the one people complain about soonest. Two decisions determine the outcome: the extraction mode, ducted or recirculating, and the airflow rate relative to the real volume of the room. Everything else, format, lighting and controls, simply follows.
What a hood does, and what it does not
A hood captures the mixture of water vapour, grease particles and odour compounds above the hob, before it settles on cabinets and walls. It is first an appliance for hygiene and for protecting the home, and only then one for odour comfort.
It does not replace the general ventilation of the dwelling. A kitchen without enough air coming in leaves the hood struggling: an appliance can only extract the air it can replace, and an over-sealed room turns a hood into a noisy fan.
Nor does it make up for poor positioning. A hood narrower than the hob lets the fumes from the outer zones escape, whatever its power. The hood should be at least as wide as the hob, and a slight overhang improves capture noticeably.
- Captures grease, vapour and odours before they settle
- Does not replace the ventilation of the home
- At least as wide as the hob
- Enough incoming air is a condition of effectiveness
Ducted or recirculating: the structural choice
In ducted mode, the loaded air is expelled outside through a duct. This is by far the more effective arrangement: moisture, heat and odours genuinely leave the home. It requires an available or feasible duct, which is not always the case in a flat.
In recirculating mode, the air passes through an activated charcoal filter that retains part of the odours, then returns to the room. Nothing leaves the home: neither the water vapour nor the heat. The result is acceptable on odours, appreciably weaker on humidity, and entirely dependent on the state of the filter.
The mode also affects noise and usable airflow. In recirculating mode the resistance of the charcoal filter reduces the real rate, and part of the airflow comes back into the room, which can be heard.
The duct deserves as much attention as the hood itself: as short and as straight as possible, of constant section, never crushed. Every bend and every superfluous metre costs airflow, and flexible corrugated ducting degrades the result badly compared with smooth ducting.
Most hoods accept both modes with a recirculation kit. It is still better to decide before buying: installation differs, and a duct planned from the start costs far less than drilling one later.
- Ducted: moisture, heat and odours genuinely leave
- Recirculating: charcoal filter, odours only, reduced airflow
- Short, straight, smooth duct of constant section
- Decide the mode before buying, not after fitting
Working out the extraction rate you actually need
Airflow is expressed in cubic metres per hour. The accepted rule is to change the air in the kitchen ten to twelve times an hour.
The calculation is immediate: multiply the floor area by the ceiling height to get the volume, then by ten or twelve. A 12 m² kitchen with a 2.50 m ceiling holds 30 m³, so the requirement is in the order of 300 to 360 m³/h.
Two corrections apply. A kitchen open to the living room must be calculated on the volume of the whole space, which raises the figure quickly. Frequent frying or rich cooking justifies aiming at the upper end.
Watch how the rate is quoted. Product sheets often give a maximum figure, measured on the intensive setting and sometimes without ducting. The useful figure is the rate in normal operation, in the mode you will actually use. An undersized hood runs flat out permanently, with the noise that implies, whereas a comfortably sized one does the same work on a middle setting, and quietly.
- Room volume multiplied by 10 to 12 air changes per hour
- Open-plan kitchen: calculate on the whole living space
- Quoted rates are usually maximums, rarely everyday figures
- A wide hood on a middle setting beats a small one at full power
The formats, and who they suit
The visor hood fits under a wall cabinet, with a visor you pull out to increase the capture area. Compact and discreet, it suits small kitchens and moderate cooking.
The telescopic hood also slides under a cabinet, and its sliding drawer widens the capture area while cooking. It is the commonest compromise between size and effectiveness.
The decorative hood, on a wall or over an island, presents itself as part of the decor. It generally offers the highest airflow and the largest capture area, but it demands visual clearance and a visible or boxed-in duct.
The canopy or integrated unit fits entirely inside a wall cabinet, leaving only the front visible. It preserves the line of the kitchen, provided the cut-out and the volume are planned for.
Downdraft hoods, which rise from behind the hob, extract as close as possible to the pans. It is an elegant solution for islands, more demanding in space beneath the worktop.
- Visor: compact, moderate cooking
- Telescopic: the most widespread compromise
- Decorative: high airflow, but a visible duct
- Integrated canopy: invisible, to be planned into the cabinet
Noise, the criterion everyone underestimates
Noise is measured in decibels on a logarithmic scale: three decibels more corresponds to a doubling of sound power. A gap that looks trivial on a spec sheet is very audible in an open-plan kitchen.
Quoted figures usually correspond to the lowest speed. Look for the full range, from minimum speed to the intensive setting, and compare like with like: a hood that is quiet at low airflow has proved nothing.
Noise does not come from the motor alone. A duct that is too narrow, crushed or full of bends creates turbulence and becomes a sound source in its own right. A properly sized hood used on a middle setting is almost always quieter than an underpowered one permanently at maximum.
Range hoods carry a European energy label, on a scale from A+++ to D, which also states fluid dynamic efficiency, grease filtering efficiency, lighting and noise level. It is the most useful document for comparing two models on equal terms.
Filters, maintenance and installation
A hood is only as effective as its filters. Metal grease filters lift out and go in the dishwasher. Monthly is a good starting rhythm, more often with frequent frying. A clogged filter collapses the airflow and makes the motor work for nothing.
Activated charcoal filters concern recirculating mode only. They cannot be washed and are replaced, generally around every six months depending on use. A saturated filter retains nothing: the hood keeps blowing without capturing any odour at all.
Installation height matters as much as airflow. Allow in the order of 65 to 70 cm above an electric or induction hob, and more, around 75 cm, above a gas hob, always respecting the figure given in the manual. Too high and the hood loses half its effectiveness; too low and it gets in the way and suffers from the heat.
Finally, plan for an accessible electrical supply and a reachable switch. Good LED lighting over the hob genuinely improves working comfort, and it is a daily use of the hood even when it is not extracting.
- Grease filters in the dishwasher, roughly monthly
- Charcoal filters replaced, never washed, in recirculating mode
- 65 to 70 cm above an electric hob, around 75 cm above gas
- Follow the height given in the manual before any general rule
Frequently asked questions
What extraction rate for a kitchen open to the living room?
The calculation covers the whole volume, not the kitchen corner. For a 40 m² living space with a 2.50 m ceiling, that is 100 m³, so ten air changes an hour already means 1,000 m³/h, a rate few hoods reach in normal use. In practice you aim for the highest reasonable airflow, favour ducted extraction, and switch the hood on before you start cooking.
Is recirculation genuinely effective?
On odours it gives an acceptable result as long as the charcoal filter is fresh. On moisture and heat, no: nothing leaves the room. It is a fallback where no duct is possible, not an equivalent of ducted extraction. Where the choice exists, ducting is better on every count.
At what height should the hood be fitted?
Follow the manual for the model first, which takes precedence. Failing that, allow in the order of 65 to 70 cm above an electric or induction hob, and around 75 cm above gas, where the flame requires greater distance. Higher and capture falls away quickly; lower and the hood obstructs movement and suffers excessive heat.
How often should the filters be cleaned?
Metal grease filters go in the dishwasher about once a month, more often with frequent frying. Activated charcoal filters, used only in recirculating mode, are replaced about every six months and never washed: washing destroys their adsorbent capacity without anything showing.
Should the hood be switched on before cooking?
Yes, a few minutes beforehand, and left running for ten to fifteen minutes afterwards. A hood switched on mid-cooking is chasing a cloud already spread through the room, whereas one already running captures vapour at source. It is the single change that most improves the result, without altering the equipment at all.
Can the hood be narrower than the hob?
It is not advisable. Fumes from the outer zones then escape the capture area and settle on neighbouring cabinets. The hood should be at least as wide as the hob; a slight overhang on each side improves the result noticeably, especially over an island where air moves freely.
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