Your chimney is loud but pulls nothing. Here is why.

The complaint arrives in the same words almost every time: the chimney is running, it is loud, and steam from the pan is still going straight up to the ceiling. Households usually conclude the motor is failing and start pricing a replacement. In most kitchens the motor is fine and the problem is sitting a few centimetres below it.

What a filter actually does

A chimney does not simply blow air away. It pulls air through a filter that catches grease before that grease reaches the motor and the ducting. Baffle filters — the metal ones with curved slats — work by forcing air to change direction sharply, so heavier oil droplets hit the metal and run down instead of carrying on through.

That means the filter is designed to get dirty. It is doing its job when it is coated. The problem is that it only keeps working if somebody takes it out and cleans it, and in a large share of Indian kitchens nobody ever has.

Why a blocked filter makes the noise worse

This is the part that misleads people. A saturated filter does not make a chimney quieter — it makes it louder. The motor is still spinning at the same speed, but it is now straining against a surface that air cannot easily pass through, and that strain is audible.

So the noise that convinces people their motor is dying is often evidence that the motor is working hard and being obstructed.

The three filter types, and which one you have

Baffle filters

Curved metal slats, usually stainless steel, arranged in a cassette that slides out. These are the most common on chimneys sold in India over the last decade. They are washable, and they are meant to be washed regularly.

Mesh filters

Layers of fine aluminium mesh. Common on older and cheaper units. They trap grease effectively but clog far faster than baffle filters and are much harder to clean properly, because the grease sits inside the mesh rather than running off a surface.

Filterless chimneys

These have no removable filter at all. Oil is separated by centrifugal force and collects in a small oil tray, which needs emptying instead. If yours is filterless and pulling poorly, check the tray and the suction inlet rather than looking for a filter that does not exist.

What cleaning covers, and what it does not

The hood, the outer body and the filters are cleaning work. A deep clean removes the hardened layer on all three, and on a chimney that has never been touched the difference in extraction is usually obvious within a minute of switching it on.

The motor and the ducting are not cleaning work. Grease that has travelled past a saturated filter and coated the fan blades or the duct interior needs a technician who can open the unit, and that is an appliance service rather than a cleaning visit.

How often, realistically

It depends far more on what you cook than on how long you have had the chimney. A kitchen that fries daily saturates a filter in a matter of months. One that mostly boils and pressure cooks can go considerably longer. Coconut oil, ghee and mustard oil all leave heavier residues than refined vegetable oils.

A practical check: slide a filter out and hold it up to a light. If you cannot see light through the gaps, it is not filtering, it is blocking.

Why it matters beyond the chimney

A chimney that is not extracting does not mean the vapour disappears. It means the vapour lands somewhere else — the ceiling above the hob, the underside of the overhead cabinets, the wall opposite. Those surfaces then need cleaning that they would not have needed at all.

It is the reason a chimney clean tends to make every other part of a kitchen stay clean longer. Fixing extraction is upstream of everything else in the room.