Why does everyone want to 'top up my freon' at the service? Does it actually get used up?
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.
House in Bragadiru, three 12,000 BTU Mitsubishi units installed 6 years ago. The units cooled fine before too. I suspect I am being taken for a ride. Does freon get used up like engine oil? See current rates on the Prices page.
What is really happening
A split that 'needs freon' every year either has a genuine leak (and a top-up is an expensive postponement) or does not need any and someone is selling something invisible. What really reduces the capacity of a 6-year-old unit is dirt: a clogged outdoor coil raises condensing pressure and cuts efficiency, and an evaporator covered in biofilm no longer transfers heat. The symptoms – cools slowly, runs longer – mimic 'low refrigerant', which is why it sells so easily. A correct service checks what can be seen: coils, fans, drain, temperature split, electrical connections (visually), not what cannot.
- Inspection: assessing condition and symptoms.
- Service check: checks and measurements appropriate to the unit.
- Cleaning: removing deposits.
- Sanitising: suitable treatment of cleaned surfaces.
The actual scope is confirmed before the visit.
- Fouling of the outdoor condenser raises pressure drop and condensing pressure, reducing the split unit's capacity and efficiency. [Science and Technology for the Built Env, 2019]
- The evaporator and condenser coils accumulate dirt over time and should be checked every year and cleaned as necessary (US DOE). [US Department of Energy – Energy Saver, 2024]
- 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]
- Daikin recommends periodic maintenance carried out by a specialist, in addition to user filter cleaning. [Daikin Europe, 2020]
What we do on site
- We measure the temperature split on each unit before touching anything – we write the values down.
- Each indoor unit: sealed waterproof cover, hose to the bucket, alkaline cleaner plus adjustable pressure wash of evaporator and roller, drain pan and hose flushed, sanitising.
- The three outdoor units in the yard: condenser washed in place, at low pressure so we do not flatten the fins.
- We restart and measure the split again: cleaning alone usually recovers 2–4 °C.
- If a unit still cools poorly after cleaning, we tell you honestly that it looks like a refrigerant problem and needs a refrigeration technician – we do not fix it and we do not sell refrigerant.
- See current rates on the Prices page.
What you can do yourself
- Ask anyone who wants to top up refrigerant to show you the gauges and explain where the leak is.
- Check whether the outdoor unit is clean – after 6 years in a yard it certainly is not.
What NOT to do
- Do not pay for annual top-ups without a leak diagnosis.
- Do not equate 'cools less' with 'low refrigerant' before the unit is clean.
Prevention
Annual cleaning of all three units, filters every two weeks – well-kept Mitsubishi units run 15 years without 'asking for freon'.
When to call us
For a maintenance service with no upsell: 0764 012 943, WhatsApp works. Bragadiru is inside our coverage area.

Related threads
How do I know the service was actually done? I want proof
Explanations and useful checks for this situation: How do I know the service was actually done? I want proof
Service, cleaning, sanitising – three different jobs or the same thing at three prices?
Explanations and useful checks for this situation: Service, cleaning, sanitising – three different jobs or the same thing at three prices?
What does an AC 'revizie' (annual service) actually include? I don't want to pay for nothing
Explanations and useful checks for this situation: What does an AC 'revizie' (annual service) actually include? I don't want to pay for nothing
How long does a proper service take and what do I need to prepare at home?
Explanations and useful checks for this situation: How long does a proper service take and what do I need to prepare at home?
Vinegar, baking soda, tea tree oil in the unit – do 'natural' remedies work?
Explanations and useful checks for this situation: Vinegar, baking soda, tea tree oil in the unit – do 'natural' remedies work?
Private kindergarten – parents want proof the units are sanitised. How do we go about it?
Explanations and useful checks for this situation: Private kindergarten – parents want proof the units are sanitised. How do we go about it?
Sources (7)
- www.tandfonline.com/doi/full/10.1080/23744731.2019.1605197
- www.researchgate.net/publication/233277421_Evaporator_Air-Side_Fouling_Effect_on_Performan
- www.energy.gov/energysaver/maintaining-your-air-conditioner
- www.osti.gov/servlets/purl/805122
- www.daikin-ce.com/content/dam/document-library/operation-manuals/ac/split/ftxf-d/FTXF-D_Op
- anpc.ro/
- www.manualslib.com/manual/3613226/Mitsubishi-Electric-Msz-Ln18vg2w.html?page=7
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.