TL;DR — Quick Answer
- General servicing: surface clean — filter, coil rinse, drain check. 30-45 mins. Do this quarterly.
- Chemical overhaul: full disassembly and deep chemical clean of every part. 2-3 hours. Do this once a year.
- If your aircon smells musty, leaks, or still feels weak after a general service, you need an overhaul.
- A general service cannot substitute for a chemical overhaul — they serve different purposes.
When homeowners call us about their aircon problems, one of the most common points of confusion is whether they need a "general service" or a "chemical overhaul." Some think they are the same thing. Some believe a chemical overhaul is only for old or broken units. Neither is true.
Understanding the difference helps you make the right call — and avoid paying for the wrong service or, worse, continuing to run a unit that needs a proper deep clean.
What Is a General Aircon Service?
A general service is routine maintenance. Think of it like an oil change for your car — regular, preventative, and relatively quick. It keeps a functioning unit running well, but it is not designed to fix a unit that has already deteriorated.
What a standard general service covers:
- Removing and washing the air filter
- Rinsing the evaporator coil with water
- Clearing the drainage pipe with a vacuum or flush
- Checking refrigerant pressure (visual check, not a full test)
- Running the unit and checking outlet temperature
Time: 30 to 45 minutes per unit. Recommended frequency: every 3 months for most Singapore homes.
What Is a Chemical Overhaul?
A chemical overhaul is a full strip-down and deep clean of the entire indoor unit. Every component is removed, soaked or cleaned with a chemical solution, and thoroughly rinsed before being reassembled. It is the most thorough cleaning an aircon unit can receive short of a full replacement.
What a chemical overhaul covers:
- Full disassembly of the indoor unit (blower fan, evaporator coil, housing, drainage tray)
- Chemical solution soak of the blower wheel (this is where mould and bacteria accumulate)
- Deep chemical clean of the evaporator coil
- Cleaning and flushing of the drainage system
- Reassembly and performance testing
- Optional: refrigerant top-up if required
Time: 2 to 3 hours per unit. Recommended frequency: once a year for most Singapore homes.
Side-by-Side Comparison
🧹 General Service
- Filter clean
- Coil rinse (surface only)
- Drain pipe check
- Gas pressure check
- 30-45 mins per unit
- $40-$70 per unit
- Every 3 months
- Good for maintained units
⚗️ Chemical Overhaul
- Full unit disassembly
- Chemical soak of all parts
- Blower wheel deep clean
- Full drain flush
- 2-3 hrs per unit
- $80-$150 per unit
- Once a year
- Essential for neglected units
When Do You Actually Need a Chemical Overhaul?
The clearest signs that a general service is no longer enough:
- Persistent musty or mouldy smell even after a recent general service
- Water dripping from the indoor unit despite the drain being cleared
- Noticeably reduced cooling that a service has not fixed
- The unit has not been deep-cleaned in over 12 months
- Visible grime or discolouration on the blower fan (if you can see it)
- Frequent or recurring water leak issues
💡 The Annual Rule
The simplest approach: schedule a general service every 3 months, and replace one of those quarterly services with a full chemical overhaul once a year. This is what most certified aircon technicians in Singapore recommend for residential units in daily use.
What About a Chemical Wash?
You may also hear the term "chemical wash" — this sits between a general service and a full overhaul. In a chemical wash, the indoor unit is cleaned with a chemical solution without full disassembly. It is more thorough than a general service but less thorough than a full overhaul.
A chemical wash is a useful option if your unit is moderately soiled but the mould and bacterial growth has not yet penetrated the blower wheel. If you are not sure which is appropriate, a technician can assess the unit and recommend the right level of cleaning.
Cost and What to Expect
At K2L Aircon, pricing is transparent and quoted before we start. There are no surprise charges at the end. See our full pricing page for current rates on general servicing, chemical washes, and chemical overhauls.
If you are unsure which service your unit needs, WhatsApp us and we will advise honestly based on what you describe. We do not upsell — if a general service is enough, that is what we will tell you.
"The majority of 'bad smell' and 'water leak' complaints we receive are resolved by a chemical overhaul. A general service cannot clean the blower wheel, and the blower wheel is almost always where the problem is."