Aircon chemical overhaul in Singapore

An aircon chemical overhaul is the most thorough cleaning a split unit usually gets. The indoor unit is taken down and dismantled, and the coil, fan and tray are cleaned with chemicals off the wall. It costs more than a chemical wash and takes longer, so it is normally booked when a unit is very dirty, smells, leaks or cools poorly despite regular servicing.

Overhaul, chemical wash and general servicing

The three common aircon cleaning services differ mainly in how far the unit is taken apart. Companies use the names in slightly different ways, so always ask what the technician will actually do.

An overhaul gives the technician access to parts that cannot be reached on the wall, such as the inside of the coil and the blower housing. It does not fix faulty parts. If the unit has an electrical or refrigerant problem, the aircon repair guide explains what to ask.

When an overhaul makes sense

There is no fixed interval for an overhaul. Companies may suggest one when a unit has not been cleaned for a long time, when black mould is visible on the fan, when water keeps dripping after servicing, or when a strong smell returns soon after a chemical wash. Ask the technician to show you photos of the inside of the unit and explain why an overhaul is better than a wash.

Be cautious if every visit ends with an upsell to an overhaul. A clean unit that cools well does not need one. The servicing price guide explains general servicing, and the chemical wash page lists published chemical wash rates if a lighter clean is enough.

What happens during an overhaul

The technician switches off the power, removes the indoor unit from its bracket and takes it apart. The coil, blower wheel, drain tray and casing are cleaned with chemical solutions and rinsed, then dried and reassembled. The unit is mounted again, connected and tested.

Because the unit is disconnected and reconnected, the work involves the refrigerant pipes and electrical connections. Ask how the company handles the pipe connections and whether it checks for leaks after reinstalling. Electrical work on the supply must be done by a licensed electrical worker; EMA's guidance on engaging licensed workers explains the rules.

Risks and how to reduce them

Taking an old unit apart carries some risk. Plastic clips and covers can be brittle, old pipe joints can leak after being disturbed, and some models are harder to dismantle than others. A careful company will check the unit first and tell you if an overhaul is not advisable.

• Ask whether the company has overhauled your brand and model before.
• Ask what happens if a brittle part breaks during the work.
• Confirm that the unit will be tested for cooling and leaks after reinstallation.
• Ask whether there is a warranty on the workmanship, and for how long.

If the unit is old and needs an overhaul plus repairs, compare the total with a replacement. The aircon installation guide covers replacement quotes.

How chemical overhaul is priced

Most companies price a chemical overhaul per indoor unit, sometimes with a lower rate for several units or a higher one for larger units and cassette types. Some packages include a gas top-up or a condenser clean; others charge these separately.

The published rates further down this page come from company websites in the HomezyPro directory, one matching per-unit rate per company with its source and capture date. Check each source for unit size limits, minimum numbers of units and GST.

• Is the price per indoor unit, and for which unit size?
• Is a gas top-up or condenser clean included?
• Is there an extra charge for cassette or ceiling units?
• Is there a minimum number of units?
• What warranty applies, and is GST included?

Preparing for the visit

Clear space under and around each indoor unit, since the technician needs room to take it down. Move furniture and cover anything that cannot be moved. Make sure the technician can reach the outdoor unit if it is part of the job, and in a condo, check whether contractors need to register or book a lift.

Ask how long each unit will take. An overhaul usually takes noticeably longer than a wash, so plan around rooms you need to use. After the work, run each unit for a while and check for cooling, unusual noise and drips before the technician leaves.

After the overhaul

A freshly overhauled unit should cool well and run quietly, without the old smell. Keep it clean with regular general servicing and by washing the filters between visits. If water starts to drip or cooling drops soon after the overhaul, contact the company under its workmanship warranty.

Chemical overhaul questions

Is a chemical overhaul better than a chemical wash?

It is more thorough because the unit is dismantled, but it is not always necessary. A chemical wash may be enough for moderate dirt. Ask the technician to show the condition of the unit and explain why it recommends one over the other.

How long does a chemical overhaul take?

It usually takes longer than a chemical wash because the unit is removed, dismantled, cleaned, reassembled and remounted. Ask the company for an estimate per unit based on your model and access.

Can an overhaul fix an aircon that is not cold?

Only if the cause is dirt, such as a clogged coil or blower. Low gas, a faulty compressor or electrical problems need diagnosis and repair. Ask the technician to check the cause before booking an overhaul.

Will my aircon leak after an overhaul?

It should not, if the work is done properly and the unit is tested. Disturbing old pipe joints can occasionally cause leaks, so ask whether the company checks for leaks after reinstalling and what its warranty covers.