Filter maintenance is the task almost nobody does often enough, yet it has the biggest single impact on running costs and air quality. A clogged filter makes the unit work harder, reduces cooling output, and accumulates mould and bacteria that end up in the air you breathe. Cleaning takes ten minutes and needs no tools. Here is how to do it properly and how often.
How often should filters be cleaned?
During peak summer with daily use, clean the filters every two weeks. With moderate use, once a month is sufficient. A more thorough clean at the start and end of the season is worthwhile, and every two to three years a professional service reaches areas you cannot access yourself. If you have pets at home or anyone in the household suffers from allergies, shorten the intervals: pet hair and pollen block filter mesh far faster than ordinary dust.
Step-by-step filter cleaning
- Switch off and unplug the unit. Always, before opening anything.
- Open the front panel. It lifts with two fingers at the sides; the filters sit directly behind it.
- Slide the filters out carefully. The plastic mesh is lightweight and bends easily if forced.
- Rinse under lukewarm running water. Running water is usually enough; for greasy build-up, a drop of mild washing-up liquid helps. No hot water as it warps the plastic frame.
- Dry fully in the shade before reinserting. A damp filter will develop mould within a day once the unit is running again.
Mistakes to avoid
Do not use a stiff brush or high-pressure jet: both damage the filter mesh and make it useless as a barrier. Never refit a filter that is still wet, because moisture on the cold evaporator coil leads directly to mould and stale odours. Do not overlook the interior of the indoor unit either: behind the filters sits the evaporator coil, which should be brushed gently, and any bent fins should be straightened with a fin comb. If you are not comfortable with that area, have a qualified technician handle it with the appropriate coil cleaner and tools.
How much does a dirty filter actually cost?
A clogged filter can increase energy consumption by 10 to 15 percent, because restricted airflow forces the compressor to run harder for the same cooling output. Blocked filters also promote ice formation on the evaporator coil, which in turn causes water leaks and additional motor strain. Ten minutes of cleaning every two weeks pays for itself directly through lower electricity bills.
When should filters be replaced?
Standard plastic mesh filters last for many years with proper care. Activated carbon and silver-ion filters are a different story: cleaning does not restore their filtration capacity, so they need to be replaced, typically once per season. If the mesh is torn, permanently yellowed, or if odours return immediately after washing, it is time to fit new ones. Replacement filters and models with high-quality filtration systems are available in our air conditioner range.