The Northeast Monsoon usually runs from December to early March. For Jurong households, that means more rainy afternoons, damp evenings and higher humidity indoors. It also means more calls from customers whose aircon has started to smell musty. This post explains why, what to look out for, and what to book before the season gets going in December 2026.
What the monsoon months mean for your aircon
Singapore is humid all year, but the monsoon months add more rain and longer stretches of damp air. When you run the aircon, it pulls moisture out of the room. That water condenses on the cold evaporator coil and drips into the drain pan.
During wetter weeks, the coil stays wet for longer, and the drain pan holds more water. Warm, wet and dark is exactly what mould likes. Dust on the coil gives it something to grow on. Within a few weeks, a unit that seemed fine in October can start to smell sour or musty at start-up.
Units in older Jurong estates such as Taman Jurong, Yuhua and Teban Gardens tend to show it first, because many of them are already past their first deep clean.
Early signs to watch for
- A musty or damp smell for the first minute or two after switching on
- Slower cooling, especially in bedrooms at night
- Dripping at night, when units run longest and produce the most water
- Dark specks on the louvres or the blower wheel when you shine a torch inside
If you notice any of these, the mould has already started. The longer it grows, the bigger the job to clear it.
Which job fits
| What you notice | What to book | Price |
|---|---|---|
| No smell, unit just due for its regular visit | General servicing | S$50 for 1 unit, S$70 for 3 |
| Mild musty smell, slower cooling | Chemical wash | From S$80 per unit |
| Strong sour smell, black specks, sludge | Chemical overhaul | S$130 to S$180 per unit |
| Dripping at night | Leak repair, often with a wash | From S$60 |
General servicing or chemical wash?
General aircon servicing in Jurong cleans the filter and the front of the coil and flushes the drain. It will not remove mould deep in the coil or on the blower wheel. If the smell is already there, a chemical wash is usually the right job.
A chemical wash leaves the unit on the wall. The technician fits a catch bag, applies a cleaning solution to the coil and blower, flushes it out, then flushes the drain pan and drain line so the loosened dirt does not cause a leak. It usually takes about 45 minutes to an hour per unit.
Booking tips for December
- Book in late November or early December if you can. Demand rises once the musty smells start.
- Weekday evenings and Sundays are available. We are open until 9 PM Monday to Saturday and until 8 PM on Sunday.
- Book a day ahead for a wider choice of slots. Same-day slots are offered in Jurong, subject to availability, but our team travels from Simei.
- Send a photo of the louvres or blower on WhatsApp. We can usually tell from that whether a wash or an overhaul fits, and give you a fixed price before we come.
Helping the coil stay dry
Between visits, a few habits help:
- Clean the filters every 2 to 4 weeks
- After a long cooling session, switch to fan mode for a few minutes so the coil can dry
- Keep bedroom doors closed while the aircon runs so it is not pulling in extra damp air
These will not replace a wash once mould has set in, but they slow it down.
Musty smell already started? Book a chemical wash in Jurong
Related service
Aircon Chemical Wash
On-wall deep clean of the coil, blower wheel and drain parts for weak cooling and mild smells.
