Your air conditioner may spend months quietly working in the background, until the first really hot Sydney day arrives and suddenly it does not cool the way it used to.

The airflow feels weaker. The room takes longer to cool. There may be an unfamiliar smell, a strange noise or even water appearing underneath the indoor unit.

Many of these problems do not appear overnight.

They often develop gradually as filters fill with dust, coils become dirty, drains begin to block and components experience normal wear.

The good news is that a small amount of regular air conditioner maintenance can make a big difference.

Some maintenance can safely be done by homeowners. Other tasks should always be left to a licensed air conditioning technician.

This guide explains the difference, shows you what to check throughout the year and helps you recognise when your air conditioner needs professional attention.

Quick Air Conditioner Maintenance Schedule

If you want the simple version, start here.

Maintenance Task	Suggested Frequency	Who Can Do It?
Check air filters	Every 2–4 weeks during regular use	Homeowner
Clean washable filters	When visibly dusty or according to manufacturer instructions	Homeowner
Wipe indoor casing and louvres	Monthly during heavy use	Homeowner
Check outdoor unit for leaves and obstructions	Monthly	Homeowner
Look for water leaks or unusual smells	Whenever the system is operating	Homeowner
Check airflow and unusual noise	Regularly	Homeowner
Professional system inspection	Around once a year for most homes	Licensed technician
Refrigerant work	When professionally diagnosed	Licensed technician
Electrical inspection	During professional servicing or fault diagnosis	Licensed technician
Deep coil or mould cleaning	As required	Professional technician

The exact maintenance schedule can vary by air conditioner model, usage and environment, so your manufacturer’s instructions should always take priority.

Why Regular Air Conditioner Maintenance Matters

An air conditioner needs unrestricted airflow to operate properly.

As dust accumulates on filters and other components, airflow can become restricted. Dirty heat-exchange surfaces can also make it harder for the system to transfer heat efficiently.

That can lead to:

• reduced cooling performance
• longer running times
• higher energy use
• poor airflow
• unpleasant smells
• increased wear
• water drainage problems
• unexpected breakdowns

Regular maintenance is therefore about more than keeping the air conditioner looking clean.

It helps maintain the operating conditions the system was designed for.

1. Start With the Air Filters

The filters are one of the easiest parts of an air conditioner to maintain and one of the most commonly neglected.

Their job is to catch airborne dust and particles before they pass through the indoor unit.

Over time, that dust builds up.

A heavily clogged filter can restrict airflow through the system.

How Often Should You Check Your Aircon Filters?

There is no universal schedule for every model or household.

However, during periods of regular use, it is sensible to inspect the filters every few weeks.

Some major manufacturers recommend cleaning primary filters approximately every two weeks when the system is used regularly.

You may need to check them more often if:

• you have pets
• your home becomes dusty quickly
• renovation or construction is happening nearby
• the air conditioner runs for many hours each day
• someone in the household is sensitive to dust
• windows and doors are frequently opened
• the property is close to a busy road

The easiest rule is:

If the filter looks dirty, clean it.

How to Clean a Split-System Air Conditioner Filter

Before doing anything, check the instructions for your particular air conditioner.

The basic process for many wall-mounted split systems is:

Step 1: Turn the Air Conditioner Off

Switch the unit off before opening the front panel.

Do not attempt to clean an operating air conditioner.

Step 2: Open the Indoor Unit

Carefully lift the front panel according to the manufacturer’s instructions.

You should see one or more mesh filters behind it.

Step 3: Remove the Filters

Slide the filters out gently.

Avoid forcing clips or plastic components.

Step 4: Remove Dust

Depending on the filter type, you may be able to:

• gently vacuum it
• rinse it with water
• wash it according to manufacturer instructions

Not every specialised filter is washable, so check the manual first.

Step 5: Allow the Filter to Dry Completely

If you wash a reusable filter, let it dry naturally in a shaded area.

Do not reinstall a wet filter.

Step 6: Reinstall It Correctly

Once completely dry, return the filter to its original position and close the front cover securely.

That simple routine can help maintain airflow between professional services.

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2. Keep the Indoor Unit Clean

The filters are only one part of the indoor air conditioner.

Dust also collects on:

• the front cover
• air outlets
• directional louvres
• surrounding surfaces

Use a soft, slightly damp cloth to wipe accessible areas.

Avoid spraying household cleaning chemicals directly into the unit.

You should also avoid reaching deeply inside the air conditioner where electrical components, the evaporator coil and fan assembly are located.

If you can see significant contamination deeper inside the unit, it may be time for professional cleaning rather than more aggressive DIY cleaning.

3. Pay Attention to the Indoor Coil

Behind the filters is the evaporator coil.

This is where heat is transferred as air moves through the indoor unit.

Because air continuously passes across it, the coil can gradually collect very fine dust and other contamination that gets past the filters.

Moisture is also naturally present around the coil while the air conditioner is cooling.

Over time, a dirty indoor coil can contribute to:

• reduced airflow
• reduced cooling performance
• unpleasant odours
• excessive moisture
• contamination inside the unit

Unlike a basic filter clean, thorough coil cleaning generally requires access to internal components.

This is where professional servicing becomes important.

AirTex’s Enhancer and Premium maintenance options include more extensive indoor coil cleaning when the system requires it.

4. Keep the Outdoor Unit Clear

Your outdoor condenser needs air.

Lots of it.

It transfers heat between the refrigeration system and the outside environment, so restricting airflow around the unit can affect performance.

Take a walk around your outdoor unit every month or so and check for:

• leaves
• grass
• weeds
• plastic bags
• cobwebs
• garden debris
• stored items
• overgrown plants

Remove loose debris that can be cleared safely.

Do not pack garden furniture, storage containers or other objects tightly around the condenser.

You should also avoid aggressive pressure washing or attempting to dismantle the outdoor unit yourself.

The condenser contains delicate coil fins as well as electrical and refrigeration components.

5. Sydney Homes Need to Think About Coastal Conditions

Air conditioners in Sydney operate in very different environments depending on the suburb.

A condenser in an inland backyard does not experience exactly the same conditions as one installed close to the coast.

Properties exposed to salty coastal air may experience corrosion more quickly.

If you live near the coast, periodically inspect the outdoor unit for:

• visible corrosion
• deteriorating metal
• damaged coil fins
• salt deposits
• rust around mounting hardware

Catching corrosion early is much better than discovering it after important components have deteriorated.

Professional servicing also gives the technician an opportunity to assess the condenser condition.

6. Check the Condensate Drain

Air conditioners do more than cool air.

During cooling operation they also remove moisture.

That moisture collects inside the indoor unit and normally exits through a condensate drain.

If drainage becomes restricted, you may notice:

• water dripping from the indoor unit
• stains on the wall
• dampness around the unit
• a musty smell
• unusual moisture inside the casing

Persistent water leakage should not be treated as normal.

A blocked drain can eventually cause damage to paint, plaster, ceilings, flooring or furniture.

If water continues to appear after the obvious external checks have been made, switch the system off and arrange an inspection.

7. Watch for Mould and Musty Smells

A musty smell when the air conditioner starts is one of the clearest signs that the system may need deeper cleaning.

Inside an air conditioner you have a combination of:

• moisture
• dust
• darkness
• organic material

Under the wrong conditions, contamination can develop around the coil, drain tray or fan assembly.

Cleaning the filters may improve the situation if they are dirty, but persistent smells can indicate contamination further inside the unit.

This may require:

• coil cleaning
• drain treatment
• fan cleaning
• anti-bacterial treatment
• mould removal

AirTex’s higher-level maintenance packages are designed for systems requiring deeper cleaning rather than only routine filter maintenance.

8. Listen to Your Air Conditioner

Homeowners often notice a problem with their ears before anything else.

A properly operating air conditioner should have a relatively consistent sound.

Pay attention if you suddenly hear:

• rattling
• grinding
• squealing
• buzzing
• clicking
• scraping
• excessive vibration

Sometimes a noise is caused by something minor, such as a loose cover.

Other noises can indicate fan, motor, electrical or mechanical problems.

A simple rule works well:

If your air conditioner suddenly sounds different, do not ignore it.

The earlier a developing fault is diagnosed, the less opportunity it has to damage another component.

9. Check the Airflow

Stand near the indoor unit while it is operating.

Does the airflow feel as strong as it normally does?

Weak airflow can have several causes.

Common possibilities include:

• dirty filters
• contaminated indoor coil
• fan problems
• incorrect settings
• duct restrictions
• other mechanical faults

Start with the filter because it is easy to check.

If the filters are clean but airflow remains noticeably weaker than before, arrange professional diagnosis.

10. Do Not Ignore Poor Cooling

Another common warning sign is an air conditioner that appears to run normally but never reaches the desired room temperature.

Before assuming something serious has failed, check:

• the operating mode
• thermostat setting
• filters
• open doors or windows
• blocked indoor airflow
• obstructions around the outdoor unit

If everything looks normal but cooling performance has clearly deteriorated, the system needs professional attention.

Potential causes can range from dirty components to refrigeration, electrical or mechanical faults.

What You Can Safely Maintain Yourself

There is plenty a homeowner can do without taking an air conditioner apart.

Generally, you can:

• inspect filters
• clean washable filters according to the manual
• wipe the indoor casing
• wipe accessible louvres
• remove loose debris from around the condenser
• trim vegetation around the outdoor unit
• watch for water leaks
• monitor unusual noises
• check whether airflow has changed
• replace remote-control batteries
• check timer and operating settings

These small tasks can make professional maintenance more effective because the system is not allowed to become severely neglected between visits.

What You Should Not DIY

Modern air conditioners contain mains electricity, high-pressure refrigerant circuits and sensitive electronics.

Do not attempt to DIY:

• refrigerant charging
• refrigerant leak repairs
• compressor work
• capacitor replacement
• electrical repairs
• circuit-board repairs
• major internal dismantling
• refrigerant pressure testing
• complicated drain repairs

In Australia, refrigeration work involving controlled refrigerants must be performed by appropriately licensed technicians.

If you are unsure whether a maintenance task is safe, stop and ask a professional.

What Does a Professional Air Conditioner Service Include?

Professional maintenance reaches areas that homeowners normally cannot safely access.

An AirTex service can include:

Filter Cleaning and Inspection

Filters are checked for dirt, deterioration and correct installation.

Drain Line Check and Test

The drainage system is checked to make sure condensation can leave the unit correctly.

Indoor Unit Inspection

The technician assesses internal cleanliness and can identify whether deeper coil cleaning is required.

Outdoor Coil Inspection

The condenser is checked for contamination, airflow problems and visible deterioration.

Refrigeration System Check

System performance is assessed for signs of refrigeration problems.

Electrical and Fan Inspection

Important electrical components and fan operation are checked for abnormal conditions.

System Performance Test

The air conditioner is operated and assessed to confirm it is heating or cooling correctly.

Service Report

AirTex provides a written record of the service and explains any faults discovered.

If repair work is required, it should be explained and quoted before additional work begins.

How Often Should You Professionally Service Your Air Conditioner?

For a typical residential system, approximately once a year is a sensible servicing schedule.

Spring is an excellent time because the air conditioner can be checked before Sydney’s summer demand begins.

However, more frequent servicing may make sense for:

• heavily used systems
• commercial premises
• systems operating throughout the year
• properties with high dust levels
• coastal properties
• homes with pets
• systems with a history of mould or drainage problems

The condition of the equipment matters more than blindly following a calendar.

If something is clearly wrong, do not wait until the next annual service.

Air Conditioner Maintenance Before Summer

Spring is the ideal time to give your system some attention.

Before the first hot spell:

1. Clean the filters.
2. Wipe the indoor unit.
3. Check the outdoor condenser.
4. Remove leaves and garden debris.
5. Run the system in cooling mode.
6. Listen for unusual noises.
7. Check that airflow feels normal.
8. Look for water leakage.
9. Check the remote and thermostat.
10. Book professional servicing if it is due.

Testing the system early gives you time to fix a problem before you urgently need cooling.

Air Conditioner Maintenance Before Winter

If you use reverse-cycle air conditioning for heating, autumn maintenance matters too.

Before winter:

• clean the filters
• test heating mode
• check airflow
• confirm the outdoor condenser is clear
• listen for abnormal noise
• ensure the system reaches the selected temperature

A reverse-cycle system that works hard during both summer and winter may require more attention than an air conditioner used only occasionally.

Signs You Should Call a Technician Now

Do not wait for scheduled maintenance if you notice:

Water Leaking Indoors

Persistent water leakage needs investigation.

Burning or Electrical Smell

Switch the air conditioner off and arrange professional inspection.

Repeated Circuit Breaker Trips

Do not repeatedly reset the breaker and continue running the system.

Ice Forming on the Unit or Pipes

Ice can indicate airflow or refrigeration problems.

Very Weak Airflow

If filter cleaning does not restore airflow, further diagnosis is required.

Warm Air in Cooling Mode

Check the settings first. If the system still cannot cool properly, arrange an inspection.

Persistent Musty Odour

The contamination may be deeper than the filters.

Unusual Mechanical Noise

Grinding, scraping or loud vibration should be investigated.

The System Stops and Starts Repeatedly

Frequent cycling can have several causes and should be professionally diagnosed if it continues.

Service, Repair or Replacement: Which Does Your Air Conditioner Need?

These three terms are often confused.

Maintenance Service

Choose servicing when the system is generally working but needs preventative inspection and cleaning.

Repair

Choose repair when the air conditioner has a specific fault.

For example:

• it will not start
• it leaks water
• it produces an error code
• it makes abnormal noise
• it is not cooling
• the breaker trips

Replacement

Replacement becomes worth considering when:

• the system is approaching the end of its useful life
• major repairs are becoming frequent
• replacement parts are difficult to obtain
• repair costs are becoming difficult to justify
• electricity consumption has increased significantly
• the system no longer suits the home
• newer equipment would provide substantial practical benefits

There is no single formula that decides whether every air conditioner should be repaired or replaced.

The age, condition, repair cost and expected remaining life all need to be considered together.

A good technician should explain your options rather than automatically recommending a new system.

Can Maintenance Reduce Air Conditioner Running Costs?

Maintenance cannot change the underlying efficiency rating of your air conditioner.

What it can do is help the equipment operate closer to the condition it was designed for.

Dirty filters and restricted airflow make the system’s job harder.

Keeping filters and airflow paths clean is therefore one of the simplest things homeowners can do to support efficient operation.

You can also reduce unnecessary energy use by:

• closing doors and windows
• using blinds and curtains
• avoiding extreme thermostat settings
• cooling only occupied areas where possible
• using zoning correctly on ducted systems
• switching the system off when it is not needed

A clean system combined with sensible operation provides the best result.

Air Conditioner Maintenance Checklist

Use this quick checklist throughout the year.

Indoor Unit

• Filters checked
• Filters cleaned if necessary
• Filters completely dry before reinstalling
• Casing clean
• Louvres clean
• Airflow feels normal
• No unusual smell
• No unusual noise
• No visible water leakage

Outdoor Unit

• Leaves removed
• Vegetation trimmed back
• Airflow around unit unrestricted
• No obvious physical damage
• No unusual vibration
• No severe visible corrosion

Operation

• Cooling mode works
• Heating mode works if reverse cycle
• Remote works correctly
• Timer settings are correct
• System reaches the selected temperature
• No unexpected error codes

Professional Maintenance

• Annual service booked
• Previous service report retained
• Recommended repairs completed
• Deeper cleaning arranged where required

Frequently Asked Questions

How often should air conditioner filters be cleaned?

It depends on the system and how often you use it.

Many manufacturers recommend checking or cleaning primary filters roughly every two weeks during regular use.

Homes with pets, high dust levels or heavy air conditioner use may need more frequent attention.

Always follow the maintenance instructions supplied with your model.

Can I wash my air conditioner filter?

Many standard mesh filters are washable, but not every air conditioner filter should be washed.

Check the manufacturer’s instructions first.

If yours is washable, allow it to dry completely before reinstalling it.

How often should an air conditioner be professionally serviced?

For most residential systems, around once every 12 months is a good starting point.

Systems that run heavily throughout the year may benefit from more frequent servicing.

What is the best time of year to service an air conditioner in Sydney?

Spring is ideal if you mainly use your air conditioner for cooling.

It gives you an opportunity to identify problems before peak summer conditions.

For reverse-cycle systems used heavily for winter heating, autumn can also be a useful servicing period.

Why is my air conditioner blowing weak air?

Start by checking the filters.

If they are clean and airflow remains weak, there may be contamination deeper inside the unit or a fan, ducting or mechanical problem that requires diagnosis.

Why does my air conditioner smell musty?

A persistent musty smell can indicate moisture and contamination around internal components such as the coil, fan or drain area.

Filter cleaning may help with minor contamination, but deeper buildup may require professional cleaning.

Can I refill air conditioner refrigerant myself?

No.

Refrigerant work should be carried out by an appropriately licensed air conditioning or refrigeration technician.

Low refrigerant is also not routine maintenance. If refrigerant is missing, the cause should be investigated.

Is annual aircon maintenance really necessary?

Regular professional inspection gives technicians the opportunity to identify contamination, drainage problems, deteriorating electrical components and other developing issues before they become larger faults.

For most residential systems, annual servicing combined with regular homeowner filter cleaning is a practical maintenance routine.

Keep Your Air Conditioner Ready for Every Season

Air conditioner maintenance does not need to be complicated.

The most useful routine is simple:

Keep the filters clean. Keep airflow around the system clear. Pay attention when performance changes. Arrange professional servicing before small problems become expensive ones.

A few minutes of homeowner maintenance throughout the year can make a noticeable difference to how cleanly and reliably the system operates.

The areas involving refrigeration, internal electrical components, deep cleaning and technical diagnosis should be left to professionals.

Need Your Air Conditioner Professionally Serviced?

AirTex services split systems, ducted systems and all major air conditioning brands throughout Sydney.

Our technicians inspect the complete system, explain anything we find and provide clear pricing before additional work proceeds.

Call AirTex: 1300 247 839

Or request a service online.