An aircon service takes under an hour a unit. The panel comes off, there is some noise, a wet towel appears, the panel goes back on, and the technician tells you it is done.
At that point you have almost no way of knowing what happened. The air feels cold, but the air felt cold on the way in too. That is the whole problem with servicing as a purchase: the part you are paying for is the part you never see.
The fix is not to become an aircon technician. It is to ask to see four things while the panel is still off, which takes about ninety seconds and changes the conversation completely.
Why cold air proves nothing
The most common way people check a service is to stand under the unit afterwards and feel the air. It is a reasonable instinct and it is close to useless.
A fan coil with a heavily fouled blower barrel still blows cold. A unit with a partially blocked drain still blows cold — right up until the pan overflows a fortnight later. A system that is slowly losing gas blows cold on the day and stops being cold in a month. None of those are things you can feel in the thirty seconds after a technician packs up.
What you can do is look at the parts that carry the evidence.
The four things worth seeing, before the panel goes back on
1. The blower barrel. This is the long black cylinder that sits behind the front grille and actually moves the air. It is the single most useful thing to look at, because it is where the dust and biofilm collect and it is the part that a rushed job skips. Clean, the fins are distinct and you can see gaps between them. Fouled, it looks like one continuous furry tube.
If your aircon smells and the barrel has not been touched, the smell is coming back. Our note on why an aircon smells musty and how to fix it for good goes into why.
2. The drain pan and where the water goes. Ask the technician to pour water through the drain pan while you watch. It should run away steadily. If it backs up, pools, or drips out of the casing, the drain is the problem and no amount of coil cleaning will change that. This is a thirty-second test and it is the one that prevents a ceiling stain.
3. The filters — and the fact that they are not the service. Filters are the part homeowners already know about, because they are the part you can reach. Plenty of people wash their own filters monthly and then assume the unit is clean. It is not. The filter catches the coarse dust; what gets past it lands on the coil and the barrel, and that is what a service is for.
Seeing clean filters handed back to you is fine. Seeing only clean filters handed back to you is the tell.
4. The coil face. The aluminium fins behind the filter should look like fins, not like felt. A grey mat across the coil face means the air is being pulled through a blanket, which is why the room takes longer to cool and why the bill drifts up.
Ask for the before and after photograph
The simplest thing you can ask any technician, anywhere, is: can you take a photo before and a photo after?
It costs nothing, it takes ten seconds, and it changes behaviour. A job that will be photographed gets done differently from a job that will not. We take before and after photos on our own jobs for exactly that reason, and because it settles the question three months later when someone asks whether the unit was actually cleaned or merely wiped.
If a technician is reluctant to photograph the work, that is information.
What the pre-check is actually for
There is a category of visit where the honest outcome is servicing will not fix this, and you want to find that out before you pay for a chemical wash that was never going to help.
That is why every service booking on aircons.sg includes a 9-point pre-check, and why a repair visit starts with it: the $45 minimum covers the visit and the diagnosis, standard repairs are quoted from there, and compressor or PCB work is quoted on site once the pre-check says what is actually wrong. The point is not the checklist. The point is that the diagnosis happens before anyone commits you to a job.
Cleaning is the wrong answer more often than people expect. What a chemical wash cannot fix sets out the faults that survive the deepest clean available, and the signs that you genuinely need a wash rather than a general service covers the other direction.
Three questions at the door
- "Can I see the blower barrel before you close it up?" Ask on arrival, not at the end. A technician who knows you will look works differently from the first unit onwards.
- "What did you find?" Not "is it done" — what did you find. A real answer sounds like "the second bedroom unit's drain was slow and the barrel in the living room was the worst of the four". A vague answer sounds like "all okay".
- "Is there anything you would not do again next time?" This is the question that surfaces the honest recommendation — that one unit is past cleaning, or that three-monthly is too often for the guest room nobody uses.
What you should be left holding
After the visit, you want a record with the number of units serviced, what was found on each, what was recommended, and the date. Not for bureaucracy — because it is the document that answers the next three arguments you might have.
It establishes servicing history if a manufacturer's warranty claim ever comes up. It tells the next technician what state the units were in. And if you rent the place out, it is the evidence of maintenance that decides who pays when something fails. Our note on the servicing fees people do not see coming covers the other half of that paperwork.
The underlying point
Aircon servicing is one of the few things you buy where the seller, the inspector and the only witness are the same person. That is not an accusation — most technicians do the job properly. It just means the ordinary consumer protections do not apply here, and the substitute is very simple.
Look at the barrel before the panel goes on. Everything else follows from that.
If you want us to do it
Tell us how many units and when they were last serviced. We will tell you whether a general service is enough or whether the unit needs more, and if the honest answer is that servicing will not fix what you are describing, we will say that before we come out rather than after.
WhatsApp us on 9107 2601 — usually a reply within five minutes. Prices for both are on the pricing page, and the deeper clean is explained on chemical wash.