Air purifier diagnostics
Your air purifier has become noisy
If the noise appeared suddenly, it is usually something loose or something in the fan. If it has grown gradually, it is more likely a loading filter making the fan work harder, or bearings starting to wear.
Important
Before you open anything
- Always unplug before reaching into the fan housing. Some units restart automatically when a panel is refitted.
- A burning or hot-plastic smell means unplug now and do not use the unit until it has been inspected.
Does this match your symptoms?
- Rattling or vibration that was not there before
- High-pitched whine
- Louder than it used to be at the same fan setting
- Clicking or scraping on start-up
Work through the causes in this order
Ordered by how often each turns out to be the real cause — not by what it costs to fix. 4 of these cost nothing to resolve.
- Most commonYou can fix thisFree to fix
1. Pre-filter or panel not seated
How to confirm it
Switch off, open the unit, and refit the pre-filter and front panel firmly. Rattles that appear right after a filter clean are nearly always this.
The fix
Reseat the filter and panel until the catches engage properly. Free.
Part: None — free to fix
- Most commonYou can fix thisFree to fix
2. Debris or hair on the impeller
How to confirm it
Unplug, remove the filters and look into the fan housing with a torch. Hair wrapped around the impeller hub and pet fur on the blades are extremely common in Indian homes and unbalance the fan.
The fix
Unplug, then clear the debris carefully with tweezers and a soft brush. Take care not to bend the blades — a bent impeller stays noisy permanently.
Part: None — free to fix
- CommonYou can fix thisUp to ₹4,500
3. Loaded filter forcing the fan harder
How to confirm it
Noise has increased gradually over months at the same fan setting, and airflow at the outlet feels weaker. Inspect the pre-filter and HEPA.
The fix
Clean the pre-filter and replace the HEPA if loaded. Noise usually drops back to normal immediately.
Part: Pre-filter cleaning, or HEPA replacement
- CommonYou can fix thisFree to fix
4. Placement amplifying the noise
How to confirm it
Units in corners, against hard walls or on tile floors reflect and amplify fan noise. Move it 30 cm from walls and try it on a rug.
The fix
Reposition. This also improves airflow, since most purifiers need clearance around the intake to work properly.
Part: None — free to fix
- OccasionalTechnician job₹1,500 – ₹5,000
5. Worn fan bearings
How to confirm it
A persistent whine or grinding that continues with the filters removed and the fan clear points at the motor bearings. Usually appears after several years of continuous use.
The fix
Motor or fan assembly replacement. On an out-of-warranty mid-range unit this can approach the price of a new purifier, so get a quote before authorising.
Part: Fan / motor assembly
- RareYou can fix thisFree to fix
6. Ioniser crackle
How to confirm it
A faint intermittent tick or crackle on units with an ioniser is often normal operation. Confirm by switching the ioniser off — if the sound stops, it is not a fault.
The fix
Leave it, or run with the ioniser off. Many owners prefer it off anyway, since ionisers can generate small amounts of ozone.
Part: None
When to stop and call a technician
- Grinding or whining persists with the filters out and the impeller confirmed clear
- Any burning smell — unplug immediately and stop using it
- The impeller is visibly damaged or wobbling
Costs shown are indicative bands for India, published so you can sanity-check a quote — they are not quotations, and they vary by brand, city and whether the technician is brand-authorised. Last reviewed 2026-08-08.