Seasonal Air Conditioning Maintenance Guide for Australian Technicians

Pre-summer AC checks (September–October)

Summer is when air conditioners work hardest, and it's when neglected systems fail. A pre-summer service catches issues before the first 40-degree day. Schedule these services proactively — contact your maintenance clients in late August or early September before they even think about turning the AC on.

• •Clean or replace filters: clogged filters reduce airflow by up to 15% and force the compressor to work harder
• •Check refrigerant levels: low gas means poor cooling and potential compressor damage — test pressures against manufacturer specs
• •Inspect condenser coils: outdoor units collect dirt, leaves, and cobwebs over winter — clean with a coil cleaner and low-pressure hose
• •Test thermostat accuracy: compare setpoint to actual room temperature with a calibrated thermometer
• •Check drainage: blocked condensate drains cause water leaks and can trip safety switches
• •Inspect electrical connections: tighten terminals, check capacitors, and measure amp draw against nameplate ratings

Pre-winter heating checks (April–May)

Ducted gas heaters and reverse-cycle systems need attention before winter. Gas systems in particular require safety checks that clients cannot do themselves.

• •Heat exchanger inspection: cracks or corrosion can leak carbon monoxide — use a combustion analyser to check flue gases
• •Gas pressure test: verify inlet and manifold pressures match the data plate
• •Flue and ventilation check: ensure flue terminals are clear and room ventilation meets AS 5601 requirements
• •Reverse-cycle defrost cycle test: run the unit in heating mode and confirm the defrost cycle activates correctly
• •Filter replacement: heating season filters clog just as fast as cooling season — replace or clean during every service

Common faults by season

Knowing what breaks and when helps you stock the right parts and set client expectations.

• •Summer: compressor failures from overwork, refrigerant leaks from thermal expansion, clogged filters causing freeze-ups, tripped circuit breakers from high amp draw
• •Autumn: drainage blockages from leaf debris, thermostat battery failures after months of disuse
• •Winter: ignition failures on gas heaters, cracked heat exchangers on older units, frozen outdoor coils on reverse-cycle systems in cold regions
• •Spring: musty smells from mould growth in idle units, rodent damage to wiring in outdoor units

Upselling maintenance contracts

A one-off service is worth $120–$200. A maintenance contract is worth $240–$400 per year, every year, with minimal acquisition cost after the first visit. The best time to offer a contract is at the end of a service call when the client has seen what you found and fixed. Frame it as protection: 'I found two issues today that would have caused a breakdown in summer. A twice-yearly service catches these early and costs less than a single emergency callout.' Offer a flat annual fee covering two visits (pre-summer and pre-winter) with priority booking during peak season.

Recording and invoicing maintenance work

Detailed records make maintenance contracts work. For each service, note the system make, model, serial number, refrigerant type and charge, filter size, and any faults found. This saves time on the next visit and demonstrates professionalism. Photograph any faults — a picture of a cracked heat exchanger or a filthy filter is more convincing than a written note. Invoice immediately after the service with an itemised breakdown of what you checked, what you replaced, and what needs monitoring.