How often should an air conditioner be cleaned?

"Is once a year enough?" — this is the most common question regarding air conditioner cleaning. The short answer: generally once a year, before the start of the season. The exact answer, however, depends on where and how you use the appliance. Let's walk through what affects the frequency.

The starting point: once per season

In an average apartment, under normal usage, pre-season annual cleaning is a good rule of thumb. The logic is simple: the unit works hardest during the cooling season, which is when the most moisture builds up inside it. If the equipment is clean at the start of the season, it will run through the busiest months in good condition — preventing mid-summer odor issues right from the start.

So, it is best not to wait for the first heatwave. If you take care of it at the beginning of the season, your air conditioner will cool properly right from the very first time you turn it on.

When is it needed more often?

If the unit runs frequently and for long periods. In an office or retail space where the air conditioner operates 10–12 hours a day, more air passes through it than in a home — so it gets dirty much faster.

If you also use it for heating. Due to heat pump operation, the equipment works in winter as well, meaning it runs for most of the year. In this case, cleaning per season practically means twice a year.

If the environment is dusty. An apartment next to a busy road, construction nearby, an indoor unit close to the kitchen, or lots of textiles — all accelerate dust and grime buildup.

If there are pets in the home. Hair and fine fluff easily enter the indoor unit, and some even passes through the filter.

If someone with allergies or respiratory sensitivities uses the space. In these cases, more frequent cleaning and disinfection changes from a matter of comfort into a health priority.

The air conditioner itself gives signs

Regardless of the calendar, there are signs indicating you shouldn't wait for the next season: a musty odor upon turning it on, slower or weaker cooling than before, louder operation, or visible dust on the air outlet grille. If you experience any of these, cleaning is due even if the previous one was done recently.

What you can do in the meantime

Between two professional cleanings, regularly removing, vacuuming, or washing the filter in lukewarm water helps a lot — every few weeks, depending on usage intensity. This slows down buildup, but does not replace deep cleaning: the heat exchanger, blower wheel, and condensate drain pan still remain inaccessible without professional equipment.

Not sure when service is due for your appliance? Feel free to reach out to the Air System team — serving Budapest and the surrounding agglomeration.