What Is an Aircon Chemical Overhaul?
Ever switched on your aircon and caught a sour smell? Mould is usually behind it, and a quick spray rarely reaches it.
An aircon chemical overhaul is our deepest clean. We take the indoor unit apart, then clean the fan motor, blower wheel, evaporator coil, drain pan and housing one by one. Each part is checked for wear, put back together and tested.
Aircon Servicing Serangoon is the local arm of Cool Earth Aircon, which Brian started in 2007 as a one-man workshop. The coil usually stays on the wall backplate and is rinsed there, while the other parts are cleaned on a sheet on the floor.
This is different from a chemical wash, where the unit stays on the wall and cleaner is flushed through it. A wash reaches a lot, but it cannot reach mould packed behind the blower wheel or jelly sludge stuck to the corners of the drain pan. Taking the unit apart is the only way to get all of it out.
Here is what you get with every overhaul:
- S$130 to S$180 per unit, fixed before work starts
- No callout fee for Serangoon
- 90-day workmanship warranty on the work
Why Overhauls Are Common in Serangoon
Many homes in Serangoon Central and Serangoon North are 1980s HDB flats. According to PropertyGuru, construction on Serangoon North Avenue 1 began in 1984, and the estate was fully on sale by 1988. A lot of these flats run older units that have only ever had basic servicing.
Singapore’s humidity sits between 70% and 90%, according to Pico Mould Removal. That keeps a coil damp, and mould settles in places a normal service never reaches. In Serangoon Garden landed homes, units in spare rooms often sit unused for months, then smell sour when they are switched back on.
That is why the chemical overhaul is one of our most common jobs here. You can read more about the local pattern on our Serangoon Central and Serangoon Garden area pages.
Signs Your Aircon Needs an Overhaul
- A strong sour smell that does not fade after a few minutes
- Black mould blowing out of the air outlet, sometimes as small specks
- Jelly-like sludge in the drain pan, often with repeat leaks
- Severe loss of cooling, even after a normal service
- No service for more than a year, or a unit over 5 years old with no deep clean
Coogle Aircon puts the usual chemical wash interval in Singapore at 12 to 18 months. A unit that has gone past that with no deep clean is a likely candidate.
Our technician always opens the unit and shows you what is inside before starting. If a chemical wash will do the job, we will say so.
Common Problems an Overhaul Solves
Black mould on the blower wheel
The blower wheel is a long drum of curved blades. Mould packs into the gaps and a spray-and-rinse cannot shift it. With the wheel out, we clean each blade until it is bare.
Sludge that keeps choking the drain
Old drain pans collect a jelly of slime and dust. It washes into the drain line and blocks it, so water spills out of the unit. Billy Aircon notes that algae and mould grow quickly in the dark, damp drip pan, so scrubbing the pan stops the source of the blockage.
Sour smell in a rarely used room
Units that sit unused stay damp inside, and mould grows fast. The site aircons.sg says mould, algae and bacteria can colonise the coil fins and drain pan within weeks in Singapore’s climate.
An overhaul clears the growth, so the room smells normal when the unit runs.
Bent fins and worn parts
With the cover off, our technician can do fin straightening on bent coil fins and check the fan motor and flare connections. Any worn part is pointed out and quoted before replacement.
Chemical Wash or Chemical Overhaul?
| Chemical Wash | Chemical Overhaul | |
|---|---|---|
| Unit taken apart | No | Yes |
| Reaches packed mould | Partly | Fully |
| Best for | Weak cooling, mild smell | Heavy mould, sour smell, sludge |
| Price | From S$80 per unit | S$130-S$180 per unit |
For context, Helpling’s Singapore guide lists overhauls at S$150 to S$250 per unit across the market. It also says they take 3 to 5 hours, against 1 to 2 hours for a wash.
Got 2 to 4 units? Ask for a time estimate when you book, so you can plan your day around it.
Looking After the Unit After an Overhaul
Once the unit is clean, keep it that way with general servicing every 3 to 4 months. The site aircons.sg also recommends quarterly servicing for most Singapore homes. Run the fan mode for a few minutes before switching off at night to help the coil dry.
For homes with many units, our servicing contract is often cheaper than booking each visit separately.
If your aircon smells sour or leaks, an aircon chemical overhaul is the fix that gets to the root. Message us to book, and we will fix the price before any work starts.