Unit only 2 years old and already smelly – was I sold a dud?
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We live in a house in Pipera, Iancu Nicolae area, Mitsubishi Electric units installed 2 years ago throughout the house (5 units). The one in the open-plan kitchen clearly smells of mould at start-up, the others do not. How is that possible at 2 years? We paid enough for them. I suspect a fault or a bad installation.
What is really happening
Mould and bacteria need three things: moisture, a suitable temperature and food. Moisture and temperature are supplied by any cooling evaporator. Food comes from dust and, in a kitchen, from cooking grease aerosols, by far the best 'fertiliser' for biofilm. The standard filter stops coarse dust but not the fine grease mist. That is why an identical unit in a bedroom is clean at 2 years while the kitchen one already smells – it is not the brand, it is what passes through it.
- Deposits or moisture inside the unit.
- The condensate drainage route.
- Sources within the room, assessed separately.
- Mould does not grow below roughly 80% surface relative humidity, but the cold surfaces inside an air conditioner constantly exceed this threshold. [WHO / NCBI Bookshelf, 2009]
- Cooling coils host bacterial and fungal communities whose load depends on climate, humidity and maintenance. [Indoor Air / PubMed, 2020]
- Filter efficiency and indoor particle concentration are the most important factors determining how fast the evaporator fouls. [Lawrence Berkeley National Laboratory / , 2002]
- Mould odour is treated by WHO and epidemiological studies as an indicator of active microbial growth, even when nothing is visible. [PLOS ONE, 2012]
What we do on site
- We inspect all 5 units, not just the kitchen one – often another one is on the way, it just does not smell yet.
- Kitchen: collection cover, cleaning solution with extended contact time for grease, pressure wash in place of the evaporator, roller and pan.
- Sanitising solution on the cleaned components.
- For the other units, if they are clean, we tell you honestly they do not need it and only do the ones that do.
- Outdoor units in the garden – washed in place, especially those next to the hedge, where pollen and fluff pile up.
- See current rates on the Prices page.
What you can do yourself
- Switch the cooker hood on before you start cooking, not after, and leave it 10 minutes afterwards.
- Switch the kitchen unit off while frying or boiling for long; restart it once the air has cleared.
- Kitchen filters – washed weekly with dish soap, not fortnightly.
What NOT to do
- Do not call the warranty service for 'smell' – it is not a fault and it is not covered; it is maintenance.
- Do not add online-bought 'carbon' filters on top of the originals – they choke the airflow and ice up the evaporator.
- Do not clean the fins with kitchen degreaser – too aggressive for aluminium.
Prevention
The kitchen unit needs annual sanitising without question; the rest of the house every 12–18 months depending on use. The hood and weekly filters make the difference between a unit that smells at 2 years and one that does not at 5.
When to call us
Call us for the whole house; we inspect on the spot for free and sanitise only what needs it: 0764 012 943, Monday–Saturday 08:00–20:00; Pipera and Voluntari are our area.
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Read also
- Bad smell from the air conditioner
- The air we breathe at home
- Symptoms of an uncleaned air conditioner
Sources (6)
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.