Air conditioners that sit unused all winter benefit from a short check before the first hot week arrives — this is also the cheapest time to find a problem, since AC service demand (and wait times) spike the moment summer heat actually hits.
Indoor unit and filter
- Replace or clean the air filter
Do this even if it looks reasonably clean — a fresh start for the season is worth the small cost. See our filter guide for ongoing intervals once the season is underway.
- Check supply and return vents are open and unobstructed
Furniture, rugs, or curtains moved during winter can end up blocking a vent without anyone noticing until the system is needed again.
- Clear the condensate drain line if accessible
A line that sat unused over winter can develop a clog that causes water backup once the system starts running regularly again.
Outdoor unit
- Clear debris from around the unit
Leaves, grass clippings and general winter debris accumulate against the outdoor unit — clear at least 60cm (2 feet) of space on all sides for proper airflow.
- Rinse the outdoor coils gently
Use a hose from the inside outward, never a pressure washer, which can bend the fins.
- Visually check for winter damage
Look for anything that fell on the unit over winter, ice damage, or a cover (if used) that needs removing before operation.
Run a test cycle early
Turn the system on for a genuine cooling test on a mild day, well before you actually need it — not just switching the thermostat and assuming it works. Let it run for at least 15–20 minutes and check that air coming from the vents is genuinely cold, not just moving.
Thermostat and settings
- Replace thermostat batteries if it uses them, and confirm the display is working correctly.
- Check the mode is set to COOL and confirm the schedule (if programmable) reflects your actual summer routine rather than a winter schedule left over from before.
When to call a technician before summer
If the test run reveals warm air, unusual noise, ice on the coil, or the system will not start at all, get it looked at now rather than waiting — our air conditioner troubleshooting guide covers the most common issues, but a pre-season technician visit is far easier to schedule than an emergency one in the middle of a heatwave.
