Chimney Making Noise? What Humming, Rattling and Grinding Mean
A noisy kitchen chimney is often a fan weighed down or thrown off balance by grease, which a deep cleaning fixes. Grinding usually means worn motor bearings, a hum with the fan not turning commonly points to a failed capacitor, and rattling is often a loose canopy, panel, duct clamp or filter plate. A high-airflow chimney that is loud on high speed but pulls little air usually has a duct problem rather than a hood problem. A short video with sound helps the technician tell which it is.
What the noise usually means
Several faults make similar noises, so treat this as a guide to the likely cause, not a diagnosis.
| What you hear | Common causes | Usually start with |
|---|---|---|
| Louder than it used to be, or humming on every speed | Grease on the fan, which makes the motor work harder | Deep cleaning |
| Hums, but the fan does not turn | A weak or failed capacitor; a fan jammed by grease; seized bearings | Switch it off at the socket to avoid overheating the motor, then a repair check |
| Grinding | Worn motor bearings; something touching the fan; the fan rubbing the housing | Repair check |
| Whine or vibration at high speed | The impeller thrown out of balance by uneven oil build-up, or a worn bearing | Deep cleaning, or a repair check for the bearing |
| Rattling or droning | An impeller unbalanced by uneven oil; a loose canopy fixing; loose mounting or panel screws; a loose duct or duct clamp | Deep cleaning or a repair check |
| Filter plates rattling or not seating | Worn clips or weakened springs holding the baffle plates | Replacing the clips and springs |
| Loud on high speed, but little pull | A powerful chimney pushed through a long, narrow or sharply bent duct | Shortening or re-routing the duct |
| Drone from an island or ceiling chimney | An unbalanced impeller, or a long duct run above the false ceiling with too many bends | Re-balancing the impeller; re-routing the duct where access allows |
Grease or a worn part?
Grease is the cause that is easiest to miss. As it builds up on the fan, the fan moves less air, the motor works harder and gets noisier, and a fan thrown off balance by grease can start to vibrate. A noisy chimney that has not been cleaned in a long time sometimes needs a deep cleaning rather than a new part, because that grease sits in the blower and fan, which a basic cleaning does not reach.
A worn motor or a failing capacitor will still be weak or noisy after cleaning, and that needs a repair. A capacitor is a small part and worn bearings can sometimes be serviced, while a burnt winding usually means a new motor. See chimney motor repair.
Checks you can do yourself
Do these with the hob off. None of them involve opening the chimney.
- Listen at each speed. Note whether the noise is there on every speed or only on high, and whether it is a hum, a grind, a rattle or a drone.
- Check the filter plates. Make sure they are seated properly. Plates that rattle or will not seat may have worn clips or springs.
- Look at the duct. Where the duct pipe is visible, look for a kink or a loose joint.
- Think about the last cleaning. If it has been more than six months since the last cleaning with daily cooking, a cleaning is due anyway, and grease may be part of the noise.
- Record a video with sound. Sound tells the technician more than a description, and it lets us carry the right spare on the first visit. Send it on WhatsApp to +91 93477 37176.
Do not open the motor housing or control panel yourself. If the motor hums without turning, gets very hot or smells of burning, switch it off at the socket.
Loud on high speed but weak: check the duct
A high-airflow chimney pushed through a long, narrow or sharply bent duct becomes loud without becoming effective, because the extra air it moves is simply fighting the pipe. When a powerful chimney is noisy but pulls poorly, the duct is usually the problem rather than the hood, and shortening or re-routing it does more than any part. A loose duct or duct clamp can also rattle. See chimney duct installation and re-routing.
What the technician does
- Finds the source. The fan balance, the bearings and the mounting inside the hood are checked, along with the panels and the duct joint.
- Grease-related noise. A deep cleaning degreases the fan and blower, and an impeller thrown off balance by oil is cleaned and re-balanced.
- Worn or loose parts. A worn bearing is replaced and the shaft re-greased, a loose canopy is re-seated and tightened, and worn filter clips and springs are replaced.
- Your decision. You are told what has failed and what the repair costs, including any part, and the repair goes ahead only if you agree. Afterwards every speed is run and the noise and suction are checked with the kitchen door shut.
Before anyone travels, you get a probable cause, a price range and the visit charge, which covers travel to your home. If you go ahead with the work, the visit charge is adjusted into the bill. See how our charges work.
Questions about a noisy chimney
Why has my chimney become so noisy?
Usually grease on the fan blades, worn motor bearings, loose screws inside the hood or a loose duct. Grease makes the motor work harder and can throw the fan off balance, which a deep cleaning fixes; worn bearings need a repair.
Why does my chimney rattle?
Common causes are an impeller thrown off balance by uneven oil, a loose canopy fixing, loose mounting or panel screws, a loose duct clamp, or baffle filter plates whose clips or springs have worn.
Why does my chimney hum on every speed?
A chimney that hums on every speed and is louder than it used to be often needs cleaning: grease makes the motor work harder and noisier. If it hums but the fan does not turn, switch it off at the socket to avoid overheating the motor; a failed capacitor is a common cause.
Is a noisy chimney a cleaning job or a repair?
A noisy chimney that has not been cleaned in a long time sometimes needs only a deep cleaning, because grease weighs down the fan. If it is still noisy after cleaning, a worn motor or a failing capacitor needs a repair.
Why is my high-suction chimney so loud?
A high-airflow hood pushed through a long, narrow or sharply bent duct becomes loud without becoming effective. Shortening or re-routing the duct usually does more than any part we could fit.