Bought a flat with 3 old units – what do I check before using them?
This page explains a situation in an editorial format. It is not an open discussion board or a verified customer review. Contact us on WhatsApp about your own appliance.
I have just bought a 3-room flat in Rahova with three air conditioners left by the seller: a Gree, an LG and one with no visible brand. I do not know how old they are, how they were used or whether they were ever cleaned. I have a 2-year-old. What should be checked before I switch them on this summer?
What is really happening
On a unit of unknown provenance, start-up is the riskiest moment: spore concentration in the room can jump tens of times at start compared with the air before, and with a 2-year-old at home that is not an experiment to run. The three check steps are: with a torch through the bottom grille you see the roller (if it is black, that is your answer), remove the filters and look at the evaporator fins (grey-green = biofilm), and look into the pan (sludge = drain on the edge). An old unit properly cleaned is as healthy as a new one; a dirty new one is not.
- Settings and room conditions.
- Restricted airflow or dirty components.
- A technical issue requiring measurements.
Do not automatically assume low refrigerant.
- EPA advises not to run an HVAC system you know or suspect is mould-contaminated, because it spreads mould throughout the home. [US EPA, 2024]
- 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]
- In children, home dampness and mould are associated with more respiratory infections and symptoms, according to recent meta-analyses. [Paediatric Respiratory Reviews, 2023]
- Washing with alkaline detergent, brushing and high-pressure rinsing reduces fungi inside the unit by more than 99%. [Indoor Air, 2023]
What we do on site
- Initial check on all three, without running them long: visual with a torch, photos, filter condition, pan, outdoor unit.
- Each unit in turn: sealed double cover, hose to the bucket, alkaline cleaner, adjustable pressure wash of evaporator, roller, pan and hose – in place; sanitising.
- The three outdoor units on the balconies: washed in place.
- Test on each: drain, temperature split, noise; we tell you if any has a technical problem (we do not repair it, but we identify it).
- We do the child's room first and recommend it twice a year. See current rates on the Prices page.
What you can do yourself
- Until we come, do not run them; if you really must, keep the child in another room and air it afterwards.
- Remove the filters and wash them – you will see immediately how neglected they were.
What NOT to do
- Do not run them 'on full to blow the smell out' – it blows the spores into the room.
- Do not use 'disinfectant' spray in the grille before cleaning.
Prevention
After the first full clean, a normal rhythm: living room and office yearly, the child's room twice a year.
When to call us
0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00. Rahova is close; for 3 units we block a whole morning.
Related threads
How can I check myself whether the unit cools as it should? Is there a simple test?
Explanations and useful checks for this situation: How can I check myself whether the unit cools as it should? Is there a simple test?
How do I check the condensate drain isn't blocked before it drips on my floor?
Explanations and useful checks for this situation: How do I check the condensate drain isn't blocked before it drips on my floor?
Pre-season check: the unit makes a new noise, is it from dirt?
Explanations and useful checks for this situation: Pre-season check: the unit makes a new noise, is it from dirt?
Baby with atopic dermatitis – does the air conditioner help or make it worse?
Explanations and useful checks for this situation: Baby with atopic dermatitis – does the air conditioner help or make it worse?
What is the correct home maintenance routine between two sanitisings? I want a list
Explanations and useful checks for this situation: What is the correct home maintenance routine between two sanitisings? I want a list
Sources (7)
- www.epa.gov/mold/brief-guide-mold-moisture-and-your-home
- www.epa.gov/mold/mold-remediation-schools-and-commercial-buildings-guide-chapter-3
- onlinelibrary.wiley.com/doi/10.1155/2023/8984619
- www.sciencedirect.com/science/article/pii/S1526054223000398
- www.osti.gov/biblio/1004161
- academic.oup.com/aje/article/194/12/3492/8249775
- pmc.ncbi.nlm.nih.gov/articles/PMC11350112/
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.