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ServiceChemical wash vs normal cleaning — what each one actually does.
About half the people who phone us asking for "the chemical wash thing" actually need a routine service. About a quarter of the people who ask for routine service actually need a chemical wash. Both groups end up surprised when we tell them — and a couple of them feel like they're being sold to.
So here's the plain English version, written so you can tell what your unit needs without taking our word for it.
What a routine service does
Routine service — what we book at RM 80 a unit — is the upkeep job. The indoor unit stays on the wall. Filters come out and get washed in soapy water. The fins get a light spray with an alkaline cleaner and rinsed. The drain pan and outlet hose get a flush. The technician checks supply-air temperature and refrigerant pressure to confirm everything is still on spec.
It's fast (about 30 minutes per unit) and it's enough between deep cleans. The job it does well: removing surface dust and the loose grime sitting in obvious places. The job it can't do: pull biofilm out of between the fins, where airflow restriction actually happens.
What a chemical wash does
Chemical wash — RM 180 a unit for a 1HP — is the annual reset. The indoor unit comes off the wall. The casing, blower wheel and drain pan are pulled apart. The coil is soaked in a non-corrosive alkaline cleaner for 8–10 minutes, then pressure-rinsed with water. The blower wheel is hand-cleaned (this is where most musty smells come from). The drain pan gets an anti-microbial. Then everything goes back together, and the unit gets a 20-minute cool-test.
It takes about 90 minutes per unit. It restores airflow that you cannot recover any other way. After a chemical wash on an overdue unit, you usually feel the difference within the first hour — colder air, less noise, no smell.
How to tell which one you need
Three quick checks at home:
- Supply-air temperature. If you stand under the louvre with the unit running on max cool, the air should feel cold enough that you'd flinch from holding your hand there. If it feels merely cool — chemical wash is overdue.
- Smell. A musty or "wet sock" smell when the unit kicks on means biofilm in the blower wheel and pan. Routine service won't fix it. Chemical wash will.
- Last chemical wash date. If it's been over 12 months — or you can't remember the date — book the wash. If it's under 9 months and the supply-air still feels cold, routine service is enough.
The blower wheel is the part nobody sees, and the part that gets disgusting fastest. Once it's biofilmed, only a wash gets it back.
The cost-per-year argument
A maintenance plan that includes three routine services and one chemical wash a year — for a single 1HP bedroom unit — runs about RM 380 a year all-in. That keeps the unit at factory-rated cooling and adds three to five years of life to it.
For comparison, a single chemical wash with no routine service in between will leave the unit running at 60–80% capacity for most of the year. You pay for the cooling difference on the electricity bill — usually RM 200–300 a year on a single unit. So skipping routine service to "save money" usually costs more than it saves.
What to ask when you book
Whether it's us or someone else, ask these three questions:
- "Will you dismantle the indoor unit or just spray it on the wall?" If they say spray on the wall — that's routine service. Don't pay chemical wash rates for it.
- "What cleaner do you use?" Should be a non-corrosive alkaline foam, not a strong acid (acid cleaners eat the fins).
- "Do I get a job sheet with supply-air temperature on it?" Should be yes, every visit. If they shrug, choose someone else.
Most disputes about aircon servicing come down to the customer paying for one thing and getting another. Knowing the difference between the two services is the cheapest insurance there is.