How to clean your air conditioner

Our tips for keeping your air conditioner unit in good condition.

Lifting the lid on air con cleaning

When you're in spring cleaning mode, you probably focus on your cupboards, floors and furnishings. It's easy to overlook the air conditioner sitting quietly on the wall (or built into the ceiling), but keeping it clean is an important step towards better air quality in your home, not to mention better energy efficiency and lower running costs.

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 the air conditioner.

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.


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Check the instructions

If you're not sure how to go about cleaning your air conditioner, check the instructions. These should detail 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.

Indoor unit air filters

The indoor air conditioner unit has air filters that need regular cleaning. It's usually a simple matter of popping open the plastic cover and removing the filter (there may be more than one).

The more clogged the filter, the harder the air conditioner has to work to push air through it. That can mean higher running costs.

Manufacturers usually recommend that you clean the filters every few weeks, but the need for cleaning really depends on how often you use the air conditioner. Simply, 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 uprightrobot 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.

Indoor unit 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.

Outdoor unit

The outdoor compressor unit should be kept clean too. Keep it 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.

Advanced cleaning

There are more steps you can take to give an air conditioner a thorough clean. For instance, the housing can be removed from the indoor and outdoor units to access the condenser coils, which also 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; worse, you could accidentally damage components and release refrigerant gas. There are also potential electrical safety hazards.

Regular service

Your air conditioning system should be professionally serviced every few years to top up the refrigerant gas, test the thermostat and make sure all the internals are in good condition. It depends on how much you use the unit, but in most cases a service every five years should be enough.

Regular cleaning and servicing will keep your air conditioner running for many years.

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