What to expect during an aircon servicing or chemical wash appointment

Booking an aircon service is easy. Knowing whether the technician actually did a proper job is harder, especially if you’re not in the room the whole time. Walking through what a service visit should look like, step by step, gives you something concrete to check against instead of just trusting the invoice.

Knowing the sequence also gives you a natural point to ask questions, right after each step, rather than trying to remember everything to ask at the very end.

Before the technician arrives

A good contractor asks a few questions when you book: how many units, what type (split, cassette, ducted), when it was last serviced, and whether you’ve noticed any specific problems like smell, noise, or weak airflow. This lets them bring the right equipment and gives you a chance to flag issues upfront rather than mentioning them halfway through the visit.

What a standard service looks like

1. Initial check. The technician looks at the unit’s general condition and asks about any symptoms you’ve noticed.
2. Filter and casing clean. The filter is removed, rinsed or cleaned, and the visible casing wiped down.
3. Gas pressure check. For a standard service, gas pressure is checked to see if a top-up is needed, which would be quoted separately.
4. Drainage check. The condensate drain is checked for blockages that could cause dripping or leaks later.
5. Test run. The unit is switched on to confirm cooling and airflow before the technician leaves.

None of these steps should carry a surprise charge on their own; our aircon servicing cost guide breaks down what each level of service should run you before you book.

What a chemical wash adds

A chemical wash is a longer, more involved process built on top of the standard steps:

Step	What happens
Dismantling	The indoor unit’s front cover, coil, and blower fan are removed
Chemical treatment	A cleaning solution is sprayed on the coil and blower to break down mould and dust buildup
Rinse	The chemical is thoroughly rinsed off to avoid residue affecting air quality
Reassembly	The unit is put back together, checked for loose panels or connections
Final test	Cooling and airflow are tested, and the technician should point out any improvement compared to before

Signs the job was done properly

After a proper chemical wash, airflow should feel noticeably stronger and any musty smell should be gone. The panels should sit flush with no water dripping and no loose fittings. A technician who gives you a clear rundown of what was actually done, and whether gas levels needed topping up, is behaving the way reviewers across this directory consistently describe as a mark of a trustworthy contractor. A vague answer, or a technician who seems rushed through the reassembly step, is a fair reason to ask more before they leave.

Multi-unit appointments

If you’re booking several units in one visit, ask upfront how the technician sequences the work, most contractors do a full pass of one unit at a time rather than doing every filter first, then every gas check, since it reduces the chance of mixing up which unit still needs what. It’s worth asking for a quick rundown per unit at the end rather than one blanket summary, since problems found on one unit, like a slow gas leak, don’t necessarily apply to the others.

What a below-standard visit looks like

The complaints that do show up in review data for this trade are specific: inconsistent workmanship between visits, corners cut on steps like the vacuum or rinse stage, and technicians who don’t explain what they actually did. None of these are hard to spot if you know what the full process should include, which is exactly why walking through the steps above before your next appointment is worth the few minutes it takes.

For contractors with a consistent track record on this, our aircon servicing and chemical wash hub is a faster way to compare providers than picking blind, and our homepage covers the wider directory if you’re also looking at installation or repair work at the same time. Our ranking method explains how we weigh review consistency against a single good or bad visit.