15-year-old unit, never cleaned inside – worth cleaning or should I replace it?
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I live in Rahova in a block and have a 12,000 BTU LG installed in 2011. It runs, it cools, but it smells and I think it has never been cleaned inside (I took the filters out: it is green-black). See current rates on the Prices page.
What is really happening
At 15 years without a wash, the evaporator has a thick layer of biofilm and caked dust, the roller is filled in between the blades, the pan has a finger of sludge. This is the case where cleaning is more laborious: longer contact time, two passes with alkaline solution, more pressure on the fins – and, honestly, the case where dismantling the roller sometimes does make sense, if the deposits have hardened. The result is spectacular though, because these deposits are exactly the source of the smell and of the start-up spores; what remains is a working unit with ten years less biofilm.
- Filters retain some airborne particles.
- The coil transfers heat; during cooling it can collect condensate.
- The blower moves air.
- The pan collects condensate for drainage.
- When a contaminated air conditioner starts, airborne fungal concentration in the room can jump from 40–920 to 5,500–100,000 CFU/m³. [Indoor Air, 2023]
- The blower (cross-flow fan) is the most fungus-contaminated component of a split unit, more than the filter or the front of the evaporator. [Indoor Air, 2023]
- Washing with alkaline detergent, brushing and high-pressure rinsing reduces fungi inside the unit by more than 99%. [Indoor Air, 2023]
- A typical evaporator fouls enough to double its pressure drop in about 7.5 years, reducing airflow by 5–7% and raising fan power by 1–10%. [Lawrence Berkeley National Laboratory / , 2002]
What we do on site
- Inspection and photos; we assess whether the roller cleans in place or needs to come out (we tell you on the spot, with the price).
- Sealed double cover, hose to the bucket, foil – a unit like this yields 5–8 litres of black water.
- First pass with alkaline solution, 10 minutes, adjustable pressure wash; second pass on remaining areas; roller turned by hand blade by blade.
- Pan and hose flushed until clear; sanitising; filters washed (we will probably recommend replacing them, they are cheap).
- Outdoor unit on the balcony washed in place – at 15 years the fins are almost opaque with dust.
- Final test: temperature split (usually up 3–4 °C), drain, noise, bucket with clear water. See current rates on the Prices page.
What you can do yourself
- Until the clean, use it as little as possible and air the room afterwards.
- Note the meter reading for a week before and a week after – you will see the difference.
What NOT to do
- Do not throw it out just for the smell – the smell is cleanable.
- Do not try to clean it yourself with sprays: at this level of dirt the spray only shifts the layer.
Prevention
After this reset, one clean a year and filters every two weeks; it will comfortably carry on for a few more years.
When to call us
0764 012 943, Monday–Saturday 08:00–20:00; Rahova is 15 minutes from us.
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Sources (3)
The information on this page is educational and based on cited sources; it does not replace medical advice. We do not do repairs, installation or refrigerant circuit work.