Pictured: a wall-mounted indoor unit with its front cover off and the coil laid out above the casing. That coil is the part a chemical wash is aimed at, and it is also the part your guests' noses meet first when the unit starts up.
Relatives are coming for Chinese New Year, or Hari Raya, Deepavali or Christmas. Perhaps it is a birthday open house, or a family member staying over for a fortnight. You look at the living room aircon and wonder whether it is good enough to face a full house for six hours straight. The question we hear is not "does my aircon need cleaning" but "what is the least I should do before people arrive, and how far ahead should I do it?" This post answers that with our published prices and steps, and a plan that works backwards from the day.
One limit up front: we can only speak for our own jobs and prices. The timing advice below is a suggestion based on how a visit goes, not a rule we publish.
Start with the rooms, not the whole flat
You do not have to wash every unit. A house full of guests uses two or three rooms hard and the rest not at all. Make a short list:
- The living room unit. It will run the longest, with the most people in the room and the front door opening and closing. This is the one that matters most.
- Wherever guests will sleep. A guest room that has sat unused for months is the unit most likely to greet a visitor with a stale smell. We have a separate post on whether a rarely used guest-room aircon still needs servicing.
- Units nobody will use. Leave them for your normal schedule.
Then walk to each unit on your list, switch it on, and run it for a few minutes before you decide anything. You are looking for the things our pages name as the signs of a unit that is overdue:
- a musty, sour or wet-cloth smell when it first switches on;
- cooling that is weaker than it used to be, so the room takes longer to get cold or never quite does;
- water dripping from the indoor unit;
- black spots or slime visible on the louvres or fins.
A unit that passes all four, and was serviced in the last few months, does not need a deep clean just because guests are coming. A unit that fails any of them is the one to fix, and it is better to find out this week than at 5pm on the day.
Which job to book
The three jobs on our price list answer three different conditions. Pick by what you saw, not by how important the occasion feels.
| What you found | The job that fits | Published price (wall units) |
|---|---|---|
| Unit runs well, no smell, last serviced within a few months | Normal servicing: dismantle the roller and blower, clean the filter, coil and drainage, flush, basic check | $55 for 1 unit, $90 for 2, $120 for 3, $160 for 4, then $35 per unit from 5 |
| Musty smell on start-up, weaker cooling, or more than 6 months since the last wash | Chemical wash: unit stays on the wall, water tray and cover fitted, chemical on the coil and blower, rinse, drain flush, test | $135 for 1 unit, $245 for 2, $345 for 3, $425 for 4, then $100 per unit from 5 |
| Unit over 5 years old and never overhauled, heavy grime on the blower wheel, or the smell came back soon after a wash | Chemical overhaul: the whole wall unit comes off the wall and every part is chemical washed | $200 for 1 unit, $370 for 2, $515 for 3, $640 for 4, then $150 per unit from 5 |
Our chemical wash page says the usual rhythm for a home is a wash every 6 to 12 months, and every 6 months if anyone in the home has allergies or asthma, the aircon runs 8 or more hours a day, or there are pets. A guest-room unit that is used lightly can stretch closer to 12 months. If one of your guests has asthma or allergies, or you are hosting a baby or an older relative, that is a reason to use the shorter end, and it is your call.
Please do not buy an overhaul "to be safe" before guests arrive. On our overhaul page the 9-point pre-check decides whether an overhaul is genuinely needed, and we say we will not strip a unit that only needs a wash. Most festive-season units are a wash or a service. An overhaul is for a unit with a history.
Why the date matters more than the job
The mistake we see, and it is a human one, is leaving the aircon to the last few days. Here is the case for working backwards from the day.
The pre-check can find something. Every booking starts with the 9-point pre-check, which takes about 10 to 15 minutes. If it finds only dirt, the service or wash you booked fixes it. If it finds something extra, such as low gas, a drainage fault or a worn part, we explain it and quote before doing anything, and you decide. A fault found a week before guests arrive can be repaired. A fault found the night before is a different conversation. That is the real reason to book early: not the clean, but the margin.
An overhaul takes the unit off the wall. The time we publish is 2 to 3 hours per indoor unit, and a 3-unit flat is usually half a day to a full day. A chemical wash is 60 to 90 minutes per unit, and a 3-unit flat is well under half a day. Normal servicing is 30 to 45 minutes per unit. Plan the visit for a day when you can be home, because the technician needs power, water for flushing the drainage, and your approval if the pre-check flags a repair.
A freshly washed unit can drip for a short while. Our post on dripping water right after a wash or service sets out what is normal and what is not. You do not want to be learning the difference with a house full of people looking at the ceiling.
As a suggestion rather than a published rule, aim to have the work finished at least a week before the first guest comes. That gives you a few days to run the units normally, smell them, listen to them, and call us if something is off, while there is still time to fix it. We confirm the earliest open slot on WhatsApp, so send your message as soon as you have your date.
A worked example with published prices
Say you live in a 3-room HDB flat with three wall units: living room, master bedroom and a small room that will be the guest room for two weeks. Here are three ways to spend the budget, using only the figures on our pages.
- Living room only, chemical wash: $135. The guest room gets nothing. Fine if the small room's unit is clean and recently serviced.
- Living room and guest room, chemical wash: $245 for 2 units, which is $122.50 per unit, a little under the single-unit price because both are done in one visit.
- All three units, normal servicing: $120, which is $40 per unit. Cheaper per unit, and the right answer when all three already run well.
Mixed jobs in a single visit, for instance a wash on the living room and a normal service on the other two, are not a single line on our price list. Do not add up numbers from different tables yourself and expect them to match. Tell us what each unit needs and we will quote the total for your flat before any work starts.
What to do on the weekend before
Assume the work is done. A few small things are worth ten minutes:
- Run the living room unit for 15 minutes with the door closed. Notice how the first minute of air smells and how the room feels afterwards.
- Look at the outdoor drain pipe outlet to see that water is leaving the unit as it should, rather than pooling or dripping where it should not.
- Wash the filters, if your model has removable ones. We have a post on washing filters yourself and where DIY stops. The coil and the drainage are not DIY.
- Do not spray anything into the unit or pour anything into the drain to hide a smell. If the smell is there after you have washed the filters, it needs a technician, not a perfume.
If you are also thinking of selling or renting out the flat, the same logic applies, with a different deadline. Our post on servicing or washing the aircon before viewings works through that one.
What a visitor actually notices
It is worth saying plainly what a guest will and will not pick up. They will notice a smell in the first minute after the unit switches on, and a room that stays warm for the first half hour. They will not notice a coil that is a bit dusty but cools well, or a service history. That is why the smell and the cooling are the two checks that matter most, and why a chemical wash, which clears the smell at its source on a fouled coil, is the usual answer when a unit fails the test. A normal service is the answer when the unit passes it.
If a unit still smells after a wash, that is usually the sign it needs the deeper job, and the pre-check will tell you so. Please do not wait until the week of the gathering to find that out.
The short version
- List the two or three rooms your guests will use, and test those units by running them and smelling them.
- Normal servicing for a unit that runs well, from $55. Chemical wash for a unit that smells, cools weakly or is over 6 months since its last wash, from $135. Overhaul only for a unit with a history, from $200.
- The 9-point pre-check is included with any service booking and tells you which job the unit needs. We quote before any work starts.
- Suggestion, not a rule: finish at least a week before the first guest arrives, so there is room to fix anything the pre-check finds.
- Prices are on our pricing page, and the full wall-unit breakdown is on the chemical wash cost page.
If you would like a plan for your flat
Tell us the date of the gathering, how many indoor units you have, which rooms guests will use, whether they are wall, cassette or ducted units, and when each was last washed or serviced. We will tell you which job each one matches and what it costs on our published prices, and we quote before any work starts. WhatsApp us on 9107 2601 and we will tell you what to expect before we come.