It's important to clean your air conditioner to maintain good air quality in your home. Filters inside air conditioners are designed to catch dust and microbes, but if not cleaned regularly they can clog up and collect moisture and even mould. That's not good for you or for your air conditioner.
Regularly cleaning your air conditioner will also mean better energy efficiency and lower running costs.
The following advice is based on split-system air conditioners (the most common type in Australian homes) but it broadly applies to ducted and wall-window models too.
Your air conditioner should have come with an instruction manual that details how to access and clean the air filters and any other user-maintainable parts. If you don't have the book any more, you may be able to download a copy from the manufacturer's website.
Make sure the unit is turned off at the wall before you do any maintenance on it.
How to clean your air conditioner filters
The indoor air conditioner unit has air filters that need regular cleaning. The more clogged the filter, the harder the air conditioner has to work to push air through it. That can mean higher running costs.
It's usually a simple matter of popping open the plastic cover and removing the filter (there may be more than one).
Manufacturers usually recommend that you clean the filters every few weeks, but it really depends how often you use the air conditioner. Simply put, the more you use it, the more often you should clean the filters. At the least, aim to clean them a couple of times a year. For example, if you mainly use the unit in summer, clean the filters in spring so it's ready for the peak season, and again when the hot season is over.
There are usually one or two main filters in the indoor unit. There might also be an air purification filter (such as a HEPA or carbon filter) that can be removed and cleaned; this type of filter will eventually need to be replaced, perhaps every year or two.
Take the filters outside for a good brush or shake. Filters can usually also be vacuumed for a thorough clean; use the vacuum cleaner's dusting brush head if you have one. (CHOICE tests and reviews a range of vacuum cleaners including barrel and upright, robot and stick vacuums.)
If the filters are very dirty and grimy, you can wash them in warm water with some mild detergent and rinse them clean. Make sure they are completely dry before putting them back in the unit.
How to clean your air conditioner's louvres
You may also be able to remove the indoor unit's louvres (the oscillating blades that direct the air flow). Give them, and the space behind them inside the unit, a thorough clean with a dry cloth or with the vacuum cleaner.
How to clean the outdoor unit of your air conditioner
Keep the outdoor compressor unit clear of surrounding grass and plants, and brush away dust, leaves and cobwebs regularly.
Running a vacuum cleaner over the air intake can help clear dust from inside.
Should you clean the condenser coils?
The housing can be removed from the indoor and outdoor units to access the condenser coils, which benefit from occasional cleaning. We advise that you leave this job to a professional though, as you could void your warranty if you do it yourself, or worse, you could accidentally damage components and release refrigerant gas. There are also potential electrical safety hazards.
Getting your air conditioner serviced
Your air conditioning system should be professionally serviced regularly – the service person will check the refrigerant gas levels, test the thermostat and make sure all the internals are in good condition. This will keep the unit running for many years.
Some manufacturers recommend the air conditioner should be serviced once a year. Others say that as long as you follow the instructions and regularly clean the filters and units, you'll only need to have the air conditioner serviced if a fault develops.
We asked CHOICE members about their air conditioner cleaning habits. Most said they clean the filters a few times each year, but only call for a service every few years or when the unit develops a fault. If in doubt, check the manual for your model or call the manufacturer for their advice.
Air conditioner cleaning cheat-sheet
Run the 'dry out' program if your air conditioner has it. This evaporates the moisture that's condensed on the heat exchanger, preventing mould and foul odours.
Clean and/or replace filter screens in the indoor unit of a split-system, or as per the instructions for your ducted system. (Do this more often if your air conditioner is always on, you live in a very dusty environment or you experience a noticeable drop in performance.)
Wipe down the indoor unit or any ducts or vents with a soft damp cloth.
Clean the outdoor unit and remove vegetation/obstructions/spiders as necessary.
Inspect HEPA or carbon filters and replace as necessary.