Why Is My Kitchen Chimney Making Noise?

The free checks: listen, look and place the noise

Ten minutes, no tools, and it usually names the cause. Do these in order.

• 1. Decide what kind of noise it is. A rattle or buzz is something loose. A roar or whoosh is air moving badly. A hum or drone that has grown over time is usually load on the fan. A grind, squeal or growl is metal on metal, and that one is the bearing. Naming it correctly is half the diagnosis.
• 2. Does the noise change with speed? Run it through every setting. A rattle that appears only at high speed is a loose panel or filter resonating. A noise present at every speed, including the lowest, is more likely the motor or bearings.
• 3. Has the suction dropped? Hold a single sheet of newspaper flat against the filter with the chimney on full. A healthy unit holds it without your hand. If it falls off or clings weakly, suction has gone — and noise rising as suction falls points straight at grease.
• 4. Press gently on the hood with the chimney running. If a light hand steadies the noise or kills it, the unit is vibrating against its mounting or against a cabinet, and the fault is in how it is fixed, not in the motor.
• 5. Where is the noise actually coming from? Stand back and listen. Noise at the hood is the fan, filters or mounting. A clacking or banging from the wall or the balcony end is the outlet flap or a bird guard. A roar along the length of the duct is airflow.
• 6. Look for the obvious. Anything resting on top of the hood, a loose oil collector cup, a filter sitting crooked, a decorative panel that has worked loose, or the hood touching an overhead cabinet.

Note what you found before reading on — it will point you at one of the sections below rather than all of them.

The commonest cause: grease-loaded filters and a fan out of balance

This is the answer in most Delhi kitchens, and it is a cleaning job rather than a repair.

Grease does not settle evenly. It builds up thicker on some parts of the filters and the fan wheel than others, and a fan wheel spinning at high speed with an uneven coating of hardened oil is out of balance in exactly the way an unbalanced washing machine drum is. The result is a hum that grows into a vibration you can feel through the hood. At the same time the choked filters make the fan work far harder against the resistance, which adds a strained, laboured note of its own.

• How to confirm it. The noise came on gradually over months rather than overnight, the suction has dropped in the same period, and the filters look and feel oily. That combination is grease, effectively every time.
• What to do about it. Switch the chimney off at the wall and let it cool. Release the filters by hand — baffle and mesh filters are designed to come out with their own catch, no tools. Soak them in very hot water with a strong degreasing detergent for twenty to thirty minutes, then scrub and dry fully before refitting. Hot water is the whole trick; grease will not shift in lukewarm water however hard you scrub.
• How often, honestly. With daily Indian cooking, every three to four weeks. Manuals written for lighter cooking suggest far longer intervals and that is why so many kitchens end up here.
• The part you cannot reach. Washing the filters does not clean the fan wheel behind them, and once the wheel itself is caked the imbalance stays. That deeper clean is a technician’s job, because it means opening the hood.

The key diagnostic, stated plainly: rising noise together with falling suction points at grease, not at the motor. A motor or bearing failure does the opposite — it makes a harsh new noise while the suction stays more or less as it was until the unit finally gives up. Anyone who tells you a gradually noisier, gradually weaker chimney needs a new motor should be asked to clean it first and demonstrate the difference.

If the suction has fallen away badly, our guide on a chimney that is not sucking smoke works through the whole suction chain, and chimney cleaning in Delhi covers what a professional deep clean involves.

Chimney rattling or vibrating? Loose filters and loose mounting

The second family of causes, and the one to suspect when the noise is a rattle or a buzz rather than a drone, and when the suction is still fine.

• Baffle filters not seated properly. The single commonest rattle. A filter that was put back after washing without clicking fully home sits a millimetre proud and buzzes against its frame in the airflow. The tell is that the rattle appeared right after a cleaning, and it is worst at high speed. Take the filters out and refit them until each one seats with a definite click and sits flush with its neighbours. Damp filters can also swell in their seats — always dry them fully before they go back.
• Filters that have warped or lost a clip. A filter that has been dropped, bent, or has a broken catch will never sit still again. These are replaceable parts and worth replacing rather than wedging.
• Loose mounting on the wall or under the cabinet. A chimney is a heavy unit hanging on brackets or bolts, and constant vibration slowly works fixings loose. The symptom is a low buzz or a knock that you can silence by pressing gently on the hood. Left alone this gets worse, because a unit that moves works its own fixings looser. Tightening the mounting is not a DIY job — it means supporting a heavy unit at height while working on its fixings and its ducting, so it goes to a technician.
• The hood touching something. In fitted kitchens the chimney sometimes ends up just brushing an overhead cabinet, a tile edge or a shutter. Vibration then transmits into the woodwork and sounds far louder than it is. Look for a rub mark or a shiny patch where the two meet.
• A loose oil collector or decorative panel. The cup or tray that catches oil, and any clip-on trim, will buzz if not properly latched. Free to check, free to fix.

Chimney loud but no suction? The duct and the outlet

If the chimney roars, whistles or booms and moves very little smoke, look at where the air is supposed to go. This is the classic new-flat and post-renovation complaint.

• A duct that is too long. Every extra metre of pipe costs suction. Where the hob sits far from an outside wall, or where the duct has to cross a kitchen to reach a shaft, the fan ends up straining against resistance: loud at the hood, weak at the hob. Nothing is broken; the installation is fighting itself.
• Too many bends. Each right-angle bend costs far more than a straight run of the same length. A duct that has to jog around a beam, a false ceiling or a cabinet run can have three or four bends in a short distance, and the air becomes turbulent instead of flowing, which is what produces that hollow roaring note.
• A crushed, kinked or sagging flexible duct. Flexible aluminium ducting is easily squashed above a false ceiling or behind a cabinet, and a partly crushed section both throttles the airflow and makes it whistle. It can also sag into a low loop that collects condensed oil, which is a separate nuisance.
• The outlet flap or damper clacking. Most installations end in a flap that opens under airflow and falls shut when the fan stops. A flap with a worn hinge, or one caught by wind from a shaft or balcony, clacks and bangs — sometimes even when the chimney is off, which is a giveaway that the noise is not coming from the unit at all.
• The bird guard or mesh at the outlet. Pigeons are a genuine problem in Delhi shafts and balconies, and the mesh fitted to keep them out rattles when it works loose, or blocks with nesting material, feathers and dust. A blocked outlet mesh makes the whole system loud and weak at once, and looks exactly like a failing motor from inside the kitchen.

You can often confirm this family from the ground: listen at the outlet end from a window or a balcony, and see whether the noise is out there rather than at the hood. Anything that involves reaching the outlet itself, working at height, or opening a duct is a technician’s job — particularly in a high-rise, where the outlet is over a drop.

Grinding or squealing? Bearings — and when to call someone

The least common cause on this page, and the one that genuinely needs a technician. Bearings let the motor shaft spin freely; as they dry out or wear, the noise changes character in a way you cannot mistake for anything else.

• What it sounds like. A grinding, growling, squealing or rumbling noise, metallic rather than airy, present at every speed including the lowest, and often worst in the first seconds after switching on.
• How to confirm it. You have already washed the filters and reseated them, the mounting is solid, the duct and outlet are clear, and the noise is unchanged. A bearing noise also tends to get steadily worse week by week rather than staying level.
• Whether it is worth fixing. Usually yes — bearings and blower assemblies are serviceable parts, and a technician can tell you whether it is a service, a part or a motor. It is not automatically a new chimney, and you should be sceptical of a verdict of “motor gone” on a unit whose filters have never been properly cleaned.

Call a technician when: the noise is metallic and present at all speeds; the noise started suddenly with a bang, clatter or burning smell; the unit smells hot or the plug point is warm or discoloured; the hood has shifted, knocked or feels insecure on its mounting; the noise persists after a proper filter wash; or the unit trips the MCB, in which case read why an MCB keeps tripping as well.

What to tell them so they arrive ready. Describe the noise in words — rattle, roar, drone, grind — and say whether it changes with speed. Say when it started and whether anything changed at the same time, such as a cleaning, a duct alteration or new cabinets. Say whether the suction has dropped as well as the noise rising. Give the make, model and rough age, whether it is ducted or recirculating, and when the filters were last washed. That last one matters more than people expect: it decides whether the visit is a deep clean or a repair.

Where to read next. If suction is the bigger complaint, start with chimney not sucking smoke. For what a professional clean covers and what drives its price, see chimney cleaning cost in Delhi. To stop the whole problem recurring, our kitchen chimney care tips set a realistic cleaning rhythm for Indian cooking. And if the chimney’s plug point sparks or smells hot, treat that as urgent and read what to do about a sparking switch or socket.