Owner Guide
How to Prepare Your Air Conditioner for Summer
Taking an hour to prepare your air conditioner for summer can save you from a sweltering night when the first heatwave hits. Units that sat quietly through winter often hide small problems, from packed filters to blocked drains. This guide walks you through a simple pre season routine, explains what each check tells you and helps you decide when a professional service makes sense.
Timing
When Should You Get Your Air Conditioner Ready for Summer?
The ideal time is spring, well before the hot weather arrives. In most of southern Australia, that means September through November. In Brisbane and other warmer areas, earlier is better, because humid heat can build from late winter.
Why start early? Because demand for technicians climbs sharply once the first hot spell hits. Everyone discovers their faults on the same weekend. By testing in spring, you give yourself time to book a repair at a calm moment rather than in the middle of a heatwave.
Early checks also let you test the system on a mild day. That way, any problem shows up while the house is still comfortable, and you are not making decisions in a rush.
Calmer Booking
Technicians are easier to schedule before the summer rush begins.
Lower Stress
A fault found on a mild day is an inconvenience, not an emergency.
Better Performance
A clean, checked system cools faster and runs more efficiently all season.
The Routine
What Are the Steps to Prepare Your Air Conditioner?
The routine below suits most split system and ducted air conditioners. It needs no tools beyond a step ladder, a vacuum and a soft brush. Work through the steps in order, and allow about an hour for a typical home.
Switch Off Safely
Turn the unit off at the remote or wall controller, then at the isolator or circuit breaker before touching anything.Clean the Filters
Remove, vacuum and gently wash the indoor filters. Let them dry fully before refitting.Wipe the Indoor Unit
Use a damp, soft cloth on the front panel and louvres. Avoid spraying liquid into the unit.Clear the Outdoor Unit
Remove leaves, grass clippings, cobwebs and anything stored against it. Keep a clear space around the unit.Check the Drain Outlet
Find where the condensate hose ends outdoors and make sure it is not crushed, buried or blocked.Restore Power and Test
Switch the power back on, choose Cool mode and run the unit for at least twenty to thirty minutes.Watch, Listen and Feel
Confirm cold air from the vents, steady operation, no unusual noises and no water dripping indoors.
Detailed filter instructions are in our guide on how to clean air conditioner filters. The sections below explain what to look for at each stage.
Indoors
What Should You Check on the Indoor Unit?
After months of rest, the indoor unit may have collected dust, insects or even a spider web or two. A quick inspection before the first run catches issues that are easy to fix now and annoying to discover later.
- Filters are clean, dry and seated flat in their guides.
- The front panel closes properly and the louvres move freely.
- There are no stains, water marks or bubbling paint on the wall below.
- Nothing blocks airflow, such as curtains, shelves or tall furniture.
- The remote has fresh batteries and the clock and timers are correct.
- No musty or burning smell appears when the unit first starts.
Water marks under the indoor unit are worth noting. They suggest the drain tray or line overflowed at some point. If you see them, keep an eye on the unit during its first long cooling run. Our pages on LG leaking water and Mitsubishi leaking water explain the common causes.
A musty smell at start up often comes from mould on the coil or fan barrel. Clean filters help, but they do not reach those parts. A professional clean is the proper fix.
Outdoors
How Do You Prepare the Outdoor Unit for Summer?
The outdoor unit does the hard work of releasing heat. To do that, it needs plenty of air flowing through its fins. Anything that blocks that airflow makes the whole system less efficient.
Walk around the unit and look closely. Garden growth during spring can be surprisingly fast. Vines, shrubs and long grass often creep right up to the fins.
Safe Owner Tasks
- Clear leaves and debris by hand with power off
- Trim plants back to leave a clear space around the unit
- Remove items stored on top or against the sides
- Check the unit sits level and steady on its base
- Confirm the drain hose is clear and not kinked
Signs to Report
- Bent or flattened fins across large areas
- Oil stains on pipework or under the unit
- Damaged or missing pipe insulation
- Rust on the casing in coastal areas
- Rattling, grinding or a fan that does not spin
Never pressure wash the fins. The jet can fold them flat and force water into electrical parts. A gentle garden hose spray from the inside outward is sometimes recommended by manufacturers, but only with the power isolated and if your manual allows it. When unsure, leave coil cleaning to a technician.
The Test Run
How Do You Test Whether Your Air Conditioner Is Cooling Properly?
A proper test run tells you far more than a quick blast of air. Choose a mild day, close doors and windows, set Cool mode at a moderate temperature and let the unit run for at least twenty minutes.
During that time, check a few things. First, the air from the vents should feel noticeably cooler than the room. Second, the unit should settle into steady running without stopping and starting repeatedly. Third, within a while you should see water dripping from the drain outlet outdoors, which shows that moisture removal is working.
If the Air Is Not Cold
Check that the mode is Cool and the set point is below room temperature. If it still blows warm, see blowing warm air on cool. Low refrigerant needs an ARCtick licensed technician.
If the Airflow Is Weak
Recheck the filters and make sure nothing blocks the unit. Then read our page on weak airflow for deeper causes.
If the Outdoor Unit Is Silent
The compressor may not be starting. Our guide on compressor not starting explains safe checks.
If It Trips the Power
Do not keep resetting the breaker. See tripping circuit breaker and book a technician.
Ducted Homes
What Extra Checks Do Ducted Systems Need Before Summer?
Ducted systems have more parts spread through the house, so they need a slightly wider check. The main filter sits behind the return air grille, usually in a hallway ceiling. Clean or replace it first.
Next, test each zone. Switch zones on one at a time with the system in Cool mode, and feel the airflow at each outlet. A zone with little or no airflow may have a stuck damper, a disconnected duct or a controller fault.
- Main return air filter is clean and correctly fitted.
- Every zone opens and delivers airflow when selected.
- Ceiling outlets are open and not blocked by furniture or fittings.
- The wall controller shows no error messages or warnings.
- No unusual noises come from the ceiling when the system runs.
- Rooms cool reasonably evenly with the doors open.
Uneven cooling is a common ducted complaint. Our pages on one room not cooling and ducted zone not working go through the usual causes. Work inside the roof space is best left to a professional, both for safety and to avoid damaging ductwork.
Your Home
How Can You Prepare Your House to Help the Air Conditioner?
The air conditioner is only half the story. The house itself determines how much heat the system must remove. Preparing the home before summer reduces the load and keeps rooms comfortable for longer.
Start with the windows, because sunlight streaming through glass is one of the biggest sources of summer heat. External shading is most effective, as it stops the sun before it hits the glass. Internal blinds and heavy curtains still help, especially on west facing windows in the afternoon.
Shade the Glass
Awnings, external blinds, shade sails and leafy plants all reduce the heat entering through windows.
Seal the Gaps
Weather strips around doors and windows keep cool air in and hot air out.
Check Insulation
Ceiling insulation in good condition slows heat coming through the roof on hot days.
Use Ceiling Fans
Moving air helps you feel cooler, so the air conditioner can run at a higher set point.
Manage Heat Sources
Ovens, dryers and old incandescent globes add heat. Use them at cooler times when possible.
Ventilate at Night
When evenings cool down, opening up the house flushes out the day’s heat before you start the unit again.
For more ways to reduce what you spend on cooling, read our guide on reducing air conditioner running costs, and try the running costs calculator.
Settings
Which Settings Should You Review Before Summer Starts?
Remotes and controllers hold on to settings from last season, including timers, heating modes and schedules. Reviewing them now avoids surprises, such as the unit switching to heat on a warm October evening.
- Change the mode from Heat to Cool or Auto as suits your home.
- Set a moderate cooling temperature, roughly 25 to 27 degrees.
- Clear old timers and set new on and off times for summer routines.
- Update app schedules if your unit is connected to WiFi.
- Check that louvre positions direct air upward for cooling.
- Confirm the clock is correct after any power interruptions.
If you are unsure which mode to use for different conditions, our guide to air conditioner modes explained helps. For set points, see the best air conditioner temperature settings. Connected units can also be scheduled remotely, as covered in our WiFi and app control guide.
Professional Service
Should You Book a Professional Service Before Summer?
Owner checks are valuable, yet they only reach the surface. A professional service goes deeper, cleaning parts you cannot safely access and measuring how well the system performs. For many households, spring is the most practical time to book.
A technician will usually clean the indoor coil and fan barrel, flush the drain, check electrical connections and inspect the outdoor unit. They can also measure temperatures and pressures to confirm the system is working as designed. Any refrigerant work must be carried out by an ARCtick licensed technician, and the technicians we send hold the licences their work requires.
Book a Service If
It has been a year or more since the last service, the unit smells musty, water marks appear on the wall, or performance dropped last summer.
Book a Repair If
The unit shows an error code, trips the power, makes grinding noises or will not cool at all after your checks.
For guidance on intervals, see how often you should service your AC. If your unit is older and you are weighing up its future, our article on whether it is worth repairing an old AC can help.
Good to Know
What About Bushfire Smoke, Storms and Heatwaves?
Australian summers bring more than heat. Smoke, dust storms and heavy rain can all affect how your system performs. A little forward planning helps the system cope.
Open more detail
During bushfire smoke events, keep windows and doors closed and run the system on recirculation. Check the filters more often, because fine particles build up quickly. Most residential air conditioners recirculate indoor air rather than drawing in fresh air, but always check your own model.
Summer storms can cause power surges and outages. If the power goes out, switch the unit off at the remote so it does not restart under load when the supply returns. Then wait a few minutes before turning it back on. Our page on not working after a power outage explains what to do if it will not restart.
Heatwaves push every system hard. Start cooling early in the day, keep blinds closed and avoid very low set points. If an error code appears during extreme heat, check the error code library for your brand, such as Daikin error codes or Mitsubishi error codes, before calling.
Questions
Frequently Asked Questions
How Long Should I Run the Air Conditioner for a Test?
At least twenty to thirty minutes in Cool mode. That gives the system time to stabilise so you can judge airflow, temperature and drainage properly.
Is It Normal for the Unit to Smell When First Turned On?
A faint dusty smell for a minute or two can happen after a long rest. A strong musty, sour or burning smell is not normal and should be checked.
Can I Clean the Outdoor Unit Myself?
You can clear debris by hand and trim plants back, with the power off. Deep cleaning of the coil and any work inside the casing is best left to a technician.
Do I Need a Service Every Year Before Summer?
It depends on how much you use the system and your home conditions. Many households benefit from an annual service. Our service interval article gives more detail.
Why Is There No Water From the Drain Outlet?
On very dry days, little moisture may form. If the air is humid and no water appears after a long run, the drain may be blocked or the system may not be cooling properly.
Should I Cover My Outdoor Unit in Winter and Uncover It in Spring?
Covers are not usually needed for reverse cycle units, which may run in winter for heating. If you do use one, remove it completely before running the system.
Are the Steps Different for Each Brand?
The routine is much the same for every major brand. Filter access, remote buttons and self clean functions vary, so check your manual. Our pages for Daikin, Mitsubishi, Panasonic, Samsung, Fujitsu and LG cover brand features.
What Should I Do if a Code Flashes During the Test Run?
Note the code and the brand, then switch the unit off. Look the code up in our error code library. A single power reset is reasonable, but a code that returns needs a technician.
Book Ahead
Where Can You Book a Pre Summer Service or Repair?
If your checks turned up a problem, or you would simply like a professional to look over the system, we can book a licensed technician in your city. Booking in spring makes scheduling easier for everyone.
Choose your city: Sydney air conditioner repairs, Melbourne air conditioner repairs, Brisbane air conditioner repairs, Perth air conditioner repairs and Adelaide air conditioner repairs. You can also browse the troubleshooting hub, or start from our main air conditioning service Australia page.
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Beat the Summer Rush
Call us to book a licensed technician for a pre season service or repair.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles