June 2, 2026 · Cairns Aircon Installers
Every Cairns local knows the feeling: it’s November, it hasn’t rained yet, the air is thick enough to chew, and the aircon becomes the most important appliance in the house. From the build-up through to the last monsoon burst around Easter, your air conditioning works harder than at any other time of year, and it’s when most systems fail.
Here’s how to get through the wet with a cool house, a healthy system and a power bill that doesn’t make you sweat all over again.
Why The Wet Is Harder On Aircon Than The Heat
Most people assume the hottest day of the year is the hardest day for their air conditioner. In Cairns it usually is not. The hardest work happens when the temperature is only in the low thirties but the humidity is sitting near saturation.
Here is why. An air conditioner does two jobs at once: it drops the temperature, and it strips moisture out of the air. Removing moisture takes a great deal of energy, and through the build-up your system spends most of its effort on exactly that. A unit that copes fine with a dry thirty-five degree day can feel completely overwhelmed at thirty-one degrees with the humidity up, because it is doing far more work than the thermometer suggests.
That is also why an oversized system is a real problem here rather than a harmless luxury. A unit that is too big cools the room quickly, satisfies the thermostat, and switches off before it has had time to pull the moisture out. The room ends up cold and clammy, which is the complaint we hear more than any other.
1. Use Dry Mode, Seriously
Through the build-up, the problem usually isn’t the temperature, it’s the humidity. Dry mode targets moisture rather than temperature, running the compressor gently to wring water out of the air. Overnight it will often keep you more comfortable than cooling mode, at a fraction of the running cost. If your controller has a “dry” droplet icon, the wet season is what it’s for.
2. Set 24–26°C And Leave It There
Cranking the set point to 18 doesn’t cool the room faster, it just makes the system run longer. Every degree below 24 adds roughly 10% to your running cost. Set it sensibly, close the room up, and let the system cycle.
3. Watch For Mould, It Moves Fast
A coil that stays cold and wet for five months straight is a mould farm. If you smell mustiness when the unit starts, don’t wait until Easter: mould you can smell is mould you’re breathing, and it spreads to the fan barrel where no filter clean can reach it. A professional deep clean before the wet is the single best thing you can do for indoor air quality in Cairns.
4. Keep The Condensate Drain Clear
The wet season is when indoor units drip through ceilings and down walls, the drain line clogs with biofilm exactly when the system is producing the most condensate. If you see water where it shouldn’t be, switch the unit off and call us before the plasterboard pays for it.
5. Check The Outdoor Unit After Every Blow
After a storm, glance at the condenser: palm fronds against the coil, mud splash, or vines growing into the cabinet all choke airflow. Keep a half-metre of clear space around it. If a cyclone warning goes up, don’t strap anything to the unit. Proper cyclone-rated mounting is part of every install we do.
6. Book Your Service Before The Rush
Every aircon company in Cairns is flat out from December to March. The smart money books an annual service in September–November, the system goes into the hard months clean, and if we find something failing, it gets fixed before the Christmas queue.
Need a pre-wet-season once-over? Book a service. Ask us about our deep clean pricing.
Get It Ready Before The Wet Starts
Everything above is easier if the system goes into the season in good shape. A sensible pre-wet checklist:
- Wash the filters properly, not just a quick vacuum
- Book the annual service in September to November, before the December rush
- Clear a half metre of space around the outdoor unit, and cut back anything that has grown into it
- Check the drain outlet is actually dripping when the system runs on a humid day. If it is not, something is blocked
- Look at the outdoor unit for rust streaks or corroded fins, especially if you are near the beaches
Signs Your System Is Losing The Humidity Battle
Worth knowing what to watch for, because these creep up slowly:
- The room hits the set temperature but still feels damp or sticky
- Condensation forming on windows, walls or the vents themselves
- Mould appearing on skirting boards, in wardrobes or behind furniture
- A musty smell that returns within days of cleaning the filters
- The system running continuously without ever cycling off
Any two of those together are worth a call. They usually point to a system that needs a proper clean, or one that was sized without a heat load calculation and is now paying for it.
After A Storm Or Cyclone Warning
Once the weather has passed, do a quick check before running the system hard:
- Clear debris, fronds and mud splash away from the outdoor coil
- Check the unit is still sitting square on its brackets or feet
- If water has been over the outdoor unit, do not run it. Call us to check it first
- If the power has been out and come back, give the system a few minutes before restarting it
Never strap or cover the outdoor unit ahead of a blow. Proper cyclone-rated mounting is part of every install we do, and a tarp or ratchet strap does more harm than good.
What To Expect On The Power Bill
Your wet season bill will be higher than your dry season bill. That is normal and unavoidable in this climate. What is not normal is a bill that jumps well beyond the previous year with no change in how you use the system. That usually means one of three things: a dirty coil, a refrigerant charge that has drifted low, or a set point that has quietly been dropped a few degrees. All three are worth investigating rather than absorbing.