Filters and heat exchangers
Dirty fins quickly cost 10 to 25 per cent of capacity. Cleaning uses specialist foam, never a garden hose.
Maintenance
Maintenance, cleaning and repair
A well-kept system uses less power, does not smell and lasts 15 years or more.
What the annual service covers
Hygiene
Damp evaporators and condensate trays breed germs. Disinfection also removes the typical musty smell.
Refrigerant
Pressure and leak testing. A slow loss cuts capacity long before the system fails outright.
Electrics and condensate
Terminals, current draw, drain and pump are checked before water runs down the wall.
What you can do yourself
The coarse dust filters in the indoor unit come out in a couple of minutes, rinse under lukewarm water and go back in dry. Every two to four weeks in summer – the single most effective thing you can do.
Also keep the outdoor unit clear: no leaves in the fins, no shrubs right in front, no snow drift in winter. Everything else – refrigerant circuit, evaporator cleaning, electrics – belongs in professional hands.
- Rinse filters every 2–4 weeks in season
- Keep 30 cm clear around the outdoor unit
- Smell, dripping or lost capacity: have it checked, don't wait
Costs and intervals
| Service | Interval | Guide price |
|---|---|---|
| Mono-split service | annual | €140–180 |
| Multi-split service (up to 3 indoor units) | annual | €190–280 |
| Hygiene clean with disinfection | every 1–2 years | €90–160 per indoor unit |
| Fault finding | as needed | from €95 call-out and first hour |
| Leak testing, commercial systems | statutory, by charge size | time and material |
Above a certain refrigerant charge, systems fall under testing and record-keeping duties in the EU regulation on fluorinated greenhouse gases. Typical domestic systems stay below that threshold; commercial systems often sit above it.
Common faults
It cools less well than it used to.
Usually filters or heat exchangers are dirty; less often refrigerant is missing. If cleaning changes nothing, the drop points to a leak that has to be found and repaired. Topping up alone is not a fix.
Water drips from the indoor unit.
Almost always a blocked condensate drain or insufficient fall. Switch the unit off immediately so water cannot reach the wall and the electrics.
It smells unpleasant.
Moisture on the evaporator. The dry or fan function after cooling helps; only a hygiene clean solves it for good.
The outdoor unit has got louder.
Often loose bracket bolts, a dirty fan or worn anti-vibration mounts. A sudden louder hum can also point to the compressor and should be checked quickly.
What a service actually involves
The engineer opens the indoor unit, cleans the filters and heat exchanger, disinfects the condensate tray and checks the drain. Refrigerant pressure, current draw and cycle times are then measured and compared with the commissioning figures.
Allow around an hour per unit. It prevents the two most common complaints: a musty smell on start-up, and water dripping from the unit.
- Clean filters and heat exchanger
- Check condensate tray and drain
- Measure pressure, current draw and output
Book a service or report a fault
Briefly describe the system and the problem. Urgent summer faults are prioritised.