Mould treatment · Chemical wash · All brands · Same week

Aircon Smells Bad?
Here's the Cause — and the Fix

A musty or foul aircon smell is almost always mould and bacteria on the evaporator coil. In Singapore's humidity, it builds up fast — and it won't clear on its own. We do a chemical wash with mould treatment and most units are odour-free within the hour.

$60
Chemical wash from
Same visit
Odour-free in ~1 hr
All brands
Daikin, Mitsu, LG…
Mould treatment included in chemical wash
Before & after photos every job
Our own technicians, no subcontractors
Common Causes

Why does your aircon smell?

Most aircon smells in Singapore come from one of these four causes. The smell type is a useful clue — here's how to read it.

Mould on the evaporator coil
The most common cause of a musty aircon smell. The indoor coil is cold and damp — ideal conditions for mould to grow. Each time the fan runs, it pulls air through the mouldy coil and into the room. Routine filter cleaning doesn't reach the coil. Only a chemical wash flushes it properly.
Fix: Chemical wash with mould treatment
Bacteria in the drain tray or line
A stagnant drain tray or partially blocked drain line becomes a breeding ground for bacteria. This produces a sour or sewer-like smell — different from the dry musty smell of coil mould. If the drain line is only partially blocked, water sits and stagnates rather than flowing out. Flushing the drain as part of a chemical wash clears it.
Fix: Chemical wash with drain flush
Dirty or clogged blower wheel
The blower wheel (the fan that pushes air through the unit) accumulates dust and grime over time. Heavy buildup can produce a stale or musty smell even after cleaning the filter, because the filter only catches particles before they reach the wheel. A chemical wash includes cleaning the blower wheel.
Fix: Chemical wash or deep clean
Electrical or burning smell
A fishy or burning smell usually means heat is affecting electrical components — capacitors, wiring insulation, or the PCB. This is less common but more serious. If you smell burning or something like melted plastic, switch the unit off. Don't run it until a technician has inspected it. We'll diagnose on-site and advise on repair vs replacement.
Fix: On-site diagnosis, repair or replacement

How AFIX eliminates aircon odours

A chemical wash isn't just a cleaning — it's a full decontamination of every surface that air touches inside your unit.

1

Inspect the coil and blower

We remove the front panel and check the evaporator coil and blower wheel directly. Visible mould or heavy grime confirms the source. We photograph the condition before we start.

2

Flush the coil with mould-killing solution

We apply a chemical cleaning agent to the coil and let it break down biofilm, mould, and debris. The solution penetrates the coil fins completely — rinsing with water alone doesn't do this.

3

Clean the blower wheel and fan

We clean the blower wheel and fan housing to remove built-up grime. This is a common source of persistent smells that return after a standard service — the blower is deep inside the unit.

4

Flush the drain tray and line

We flush the drain pan and drainage pipe to clear stagnant water and bacteria. A clean drain prevents the sour smell from returning and stops water from overflowing.

5

Run the unit and confirm odour-free

We run the unit for 10–15 minutes before leaving to confirm the smell is gone. You'll know it's working before we pack up. Most units are completely odour-free at this point.

Pricing

What it costs to fix a smelly aircon

A chemical wash fixes the vast majority of aircon smell problems. We quote clearly before starting — no surprises on arrival.

Routine
Standard Servicing
If the smell is mild and recent
1 unit$50
2 units$30 / unit
3+ units$25 / unit
Book via WhatsApp ↗
Includes filter clean, coil wipe-down, drain check. For persistent smells we recommend chemical wash.
Repair
Electrical / Component
For burning or fishy smell
DiagnosisIncluded
Repair quoteOn-site
Call-out feeNone
Book via WhatsApp ↗
If you smell burning, switch the unit off and contact us before running it again.
Not sure which service you need? Just describe the smell via WhatsApp and we'll advise before booking. Musty or stale = chemical wash. Burning or electrical = call us before running the unit. Ask on WhatsApp →

Aircon smell — your questions answered

Still not sure? Just ask us directly.

Ask on WhatsApp →
Why does my aircon smell musty?+
A musty smell almost always means mould and bacteria have built up on the evaporator coil. Singapore's humidity means moisture is constantly passing over the coil — if the unit isn't serviced regularly, mould takes hold and releases that distinctive stale smell every time the fan runs. A chemical wash with mould treatment clears it completely.
Will a chemical wash remove the aircon smell?+
Yes — for the vast majority of aircon smell problems, a chemical wash is the correct fix. It fully flushes the evaporator coil, drain pan, and drainage line with a cleaning agent that kills mould and bacteria. Most units are completely odour-free within 30 minutes of the job finishing.
Why does my aircon smell like fish or burning?+
A fishy or electrical smell often points to overheating electrical components — the plastic housing around capacitors or wiring can give off a fish-like odour when warm. A burning smell is more serious and usually means a motor or PCB issue. If you smell burning, turn the unit off and WhatsApp us — don't run it until it's been checked.
How much does it cost to fix an aircon that smells?+
A chemical wash (the most common fix) costs $60 for 1 unit, $50/unit for 2 or more. Standard servicing starts at $50 if the cause is minor. If the smell is electrical, we diagnose on-site and quote separately. We don't charge a call-out fee.
Can you fix the smell the same week?+
Yes — WhatsApp us your unit count and block and we'll confirm a same-week slot. Most smell issues are resolved in a single visit of one to two hours.
My aircon smells only when I first turn it on — is that normal?+
A brief musty smell when starting up is common and usually means light mould buildup on the coil. If it clears in 5–10 minutes, it's mild. If it persists or is strong, the coil needs a proper chemical wash. Running it more often won't fix it — the mould source needs to be physically removed.

Aircon smells bad? Let's fix it this week.

WhatsApp us what the smell is like and how many units — we'll confirm a slot and have it odour-free the same day.

WhatsApp us · +65 9451 3022 All aircon services