Choosing a cooker hood: extraction, airflow and noise

Should the hood extract to the outside or recirculate?

Extract to the outside if you can: only a ducted hood removes moisture and heat from the kitchen, while a recirculating hood filters the air and blows it back in.

• Ducted extraction pushes kitchen air outside through a wall or roof outlet. It is the most effective option, but every cubic metre extracted has to be replaced by fresh air, which in winter means heat loss and, in airtight homes, an air inlet.
• Recirculation passes the air through the grease filter and an activated carbon filter that absorbs smells. Steam stays in the room, so you still need to air the kitchen, and the carbon filter has to be replaced or regenerated at the interval the manufacturer gives.

Hob extractors that pull vapour down beside or through the hob count as cooker hoods too and carry the same label. Whichever design you choose, a short, smooth duct of the diameter the manufacturer specifies matters: long runs, tight bends and reducers lower the airflow you actually get.

How much airflow does your kitchen need?

A widely used rule of thumb is to replace the kitchen’s air six to twelve times an hour, so multiply the room volume in cubic metres by 6 to 12 to get the airflow in m³/h.

A kitchen of 4 by 3 metres with a 2.5-metre ceiling holds 30 m³, which by this rule calls for roughly 180 to 360 m³/h; an open-plan kitchen and living area needs considerably more. Use the lower end for light cooking and the upper end if you fry or sear often. Compare the airflow at the highest normal setting, not at boost: the label and product sheet list them separately.

The table groups hoods by maximum airflow, as in our cooker hood overview. Under EU ecodesign rules, a hood whose top setting exceeds 650 m³/h must drop back to 650 m³/h or less automatically after a short time, so boost is for the first minutes of heavy frying, not for the whole evening.

How loud will it be while you cook?

The label states sound power in dB(A) at the highest normal setting, and a difference of 10 dB sounds roughly twice as loud.

Sound power describes the source, so it is higher than the sound pressure you hear at the hob, but it compares models fairly. Boost is excluded from the label value; where a hood has one, the product information sheet gives its noise separately. A hood with more airflow than you need can run on a lower, quieter step most of the time, which is often the better buy than a smaller hood at full speed. For open-plan living spaces, start with the quietest cooker hoods.

What do the four letters on a hood label mean?

Besides the overall energy class, the label rates how efficiently the fan moves air, how efficient the lighting is and how much grease the filter catches.

The yearly kWh on the label assume 60 minutes of fan and 120 minutes of light a day, adjusted by a factor that lets a less efficient fan run longer. Labels have run from A+++ to D since 2020 under Delegated Regulation (EU) No 65/2014. A hood can score well on energy and still filter grease poorly, which matters for the cupboards above it and, with recirculation, for the carbon filter. The hood label explainer covers each field.

Is an extractor hood safe with a fireplace or gas boiler?

Only with precautions: a ducted hood can lower the air pressure in the home enough to pull flue gases back out of a stove, fireplace or open-flued boiler that takes its combustion air from the room.

Building rules in many countries therefore require a safety device, such as a window contact switch that lets the hood run only while a window is open, or a pressure monitor. Ask your chimney sweep or heating installer before buying. Recirculating hoods do not create this negative pressure, which is one reason they are chosen in homes with a wood stove.

How do you maintain a hood, and can it be repaired?

Clean the metal grease filters regularly, replace carbon filters on schedule, and expect to rely on the manufacturer’s goodwill for parts, because no EU rule requires them.

Most metal grease filters can go in the dishwasher. A clogged filter cuts airflow and makes the fan louder, and grease building up in a duct is a fire risk. Cooker hoods have no EU ecodesign requirement on spare parts or repair information and are not covered by the EU right-to-repair directive. Fan motors, switches and LED modules are the usual replacement parts, so check whether the manufacturer lists them before you buy.

What does a cooker hood cost to run?

Usually little: the label’s yearly kWh, multiplied by your electricity price, gives the running cost for the standard use pattern.

The bigger cost of a ducted hood can be the heated air it sends outside in winter, which no label captures. Electricity prices vary widely across Europe, see electricity prices by country. Replacing a working hood rarely pays back on electricity alone; if you are weighing it against a repair, compare price, expected life and running cost with the total cost of ownership calculator.

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