Air Filter Cleaning and Replacement

On a wall mounted split, the filters are behind the front panel, which lifts up. There are usually two washable mesh screens sitting over the indoor coil, and often a small carbon or catechin insert that is not washable and does need replacing.

On a ducted system, the main filter is at the return air grille, which is the large grille in a hallway ceiling or wall. That is a replaceable panel or a washable pleated media, and it is the one that gets forgotten because it is out of sight and takes a screwdriver and a ladder. Some ducted systems have a second filter at the indoor fan coil in the roof, which is where we tend to find years of accumulated dust.

Restricted airflow across the indoor coil means the refrigerant does not absorb the heat it should. In cooling, that drops the coil temperature until moisture on it freezes, so the system ices up, output collapses and water appears when it melts. In heating, the unit trips out on high temperature or simply takes far longer to warm the room.

Either way the compressor runs longer for the same result, which costs money and wears the system. We have attended plenty of no cooling callouts in January that were a filter, and every one of them was avoidable.

Your air conditioner recirculates the air in your house many times an hour, so it is the single biggest opportunity to catch what is floating in it. In the west that means fine road dust, pollen through the grass season, pet dander, and smoke on the days when there is a fire somewhere.

Upgrading the return air media on a ducted system to a higher grade filter captures much finer particles than the standard media does, which makes a real difference for households with asthma or hay fever. There is a trade off and we will be straight about it. A denser filter creates more resistance, so it has to be matched to what your fan can handle and changed more often. Fitting an aggressive filter to a system that cannot pull air through it just moves the problem from your lungs to your compressor.

Split system mesh filters want a wash every one to three months while the system is in daily use, and a check at the start of each season regardless. Ducted return air media should be looked at every three months and replaced at least annually.

Anything that puts particles into the air shortens those intervals. Renovation dust is the worst offender, followed by pets, then living on a main road or near a construction site. Households in the newer Tarneit and Truganina estates with ongoing building nearby often need to double the frequency for the first few years.

Sometimes the filter is fine and the airflow still is not. The usual culprits are a coil that has silted up behind the filter, a blower wheel packed with dust, or on ducted systems a collapsed or disconnected duct run in the roof.

Those are not filter jobs. A coil and blower clean is a proper service item, and duct repairs need someone in the roof space with lights and a camera. If we come out to change filters and find one of those, we will show you photos and price the fix rather than putting a fresh filter over a problem.