Why Is My Kitchen Extractor Fan Not Working Properly?

The most common reason a kitchen extractor fan stops working properly is a blocked or greasy filter restricting airflow, followed by a blocked or kinked duct run, a worn motor, or (for recirculating hoods) a saturated carbon filter that needs replacing rather than cleaning. Work through these in order before assuming the unit is faulty.

1. Check the grease filter first

Metal mesh grease filters sit directly under the hood and catch cooking grease before it reaches the fan and ducting. Over a few months of regular cooking, they clog with a sticky film that noticeably reduces airflow and can make the fan sound like it's straining. Most metal filters can go in the dishwasher or be soaked in hot water with degreaser — aim to clean them every 4–6 weeks if you cook often.

2. Recirculating vs ducted — different fixes

There are two types of extractor, and the fix depends on which you have:

• Ducted (extractor) hoods push air outside through ductwork. If airflow is weak, check the duct run itself for kinks, crushed sections, or a blocked external vent — birds' nests and general debris in an external vent cover are a surprisingly common cause of poor extraction.
• Recirculating (recycling) hoods pull air through a carbon filter that absorbs odours and return the air to the room. These carbon filters aren't washable — they need replacing roughly every 6 months, and a saturated filter will make the whole unit seem weak even though the fan itself is fine.

3. Motor and electrical issues

If filters are clean and ducting is clear but the fan is still weak, noisy, or not running at all, the motor itself may be failing — a common wear point after 8–10+ years of regular use. A grinding or rattling noise often points to worn bearings. At this stage it's usually more cost-effective to replace the unit than repair it, unless it's a premium integrated model. Any electrical fault (fan not powering on at all) should be checked by a qualified electrician rather than opened up yourself.

4. Ducting problems during a renovation

If your extractor has never worked well since a kitchen renovation, the duct run may simply be too long, have too many tight bends, or vent into a loft space instead of outside — all of which severely reduce extraction performance regardless of how good the fan unit is. Poor extractor ducting is a genuinely common renovation mistake that's expensive to fix after the kitchen is finished, so it's worth having a fitter confirm the duct route and length before installation, not after.

When to call a professional

• The fan doesn't power on at all (electrical fault)
• Persistent grinding, rattling or burning smell from the motor
• You suspect the ducting itself needs re-routing
• You're renovating and want the extraction properly specified from the start

Cleaning filters and checking the external vent is safe DIY territory. Anything involving the motor, wiring, or duct re-routing is best left to a qualified fitter or electrician.

Preventing problems before they start

A simple maintenance routine avoids most extractor problems: clean metal grease filters every 4-6 weeks, replace carbon filters on recirculating hoods roughly every 6 months, and check the external vent cover once or twice a year for debris or nesting. Keeping a note of when filters were last cleaned or replaced (a phone reminder works well) is a small habit that meaningfully extends the life of the unit and keeps extraction performance consistent. If you are planning any kitchen renovation work, it is also the right moment to review whether your current extraction is even correctly specified for your hob — under-specifying ventilation is one of the most common kitchen renovation mistakes, and it is far cheaper to correct at the planning stage than after the units are fitted.

Recirculating vs ducted: which is actually better?

Ducted extraction is generally the more effective option since it removes cooking moisture and smells from the house entirely, rather than filtering and recirculating the same air. It is the better choice where a viable duct route to an outside wall or roof exists. Recirculating hoods make sense where ducting is genuinely impractical, such as an island position far from an external wall, but expect noticeably weaker odour and moisture control compared with a properly ducted system, particularly for households who cook with a lot of frying or steam.

Signs it is time to replace rather than repair

If the unit is over 10 years old, replacement parts are hard to source, or the noise and weak extraction persist even after new filters and a clear duct check, replacing the whole unit is usually more cost-effective than continuing to repair an ageing motor. Modern extractor fans are also considerably quieter and more energy-efficient than older models, so a replacement often brings a genuine day-to-day improvement beyond just fixing the fault.