Can I clean only the indoor unit? The outdoor one 'doesn't come into the house'
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.
My logic (Aviației, new block, 12,000 BTU Mitsubishi, 3 years old): the air I breathe goes through the indoor unit, not the outdoor one. So for health, what matters is the indoor unit. Why does everyone insist on the outdoor one too? Isn't it just to charge more?
What is really happening
A split is a single circuit: the heat the evaporator takes from the room must be rejected outside by the condenser. When the outdoor fins are clogged, condensing pressure rises, the compressor draws more for the same effect, and capacity drops – condenser fouling literature documents exactly this chain. The US Department of Energy recommends annual checking of both coils, not only the indoor one. The good news is the outdoor unit is washed in 15–20 minutes in place, is the 'cheapest' part of the visit, and needs no cover or sanitising.
- Keep the air intake clear.
- Do not obstruct discharged air.
- Service access and clearances depend on the manual and location.
- 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]
What we do on site
- Indoor: sealed double cover, hose to the bucket, alkaline detergent, adjustable pressure wash of evaporator, roller, pan and hose, sanitising, filters – the health part.
- Outdoor on the technical balcony: unit off, condenser detergent, low-pressure wash in place, fan and grille – the efficiency part.
- We measure the temperature split before and after – with a dirty outdoor unit the recovered split shows in the numbers.
- See current rates on the Prices page.
What you can do yourself
- Look at the outdoor unit: if the fins have a uniform grey layer, the unit is paying on your bill.
- Keep 50 cm clear around the unit.
What NOT to do
- Do not accept 'indoor 200 / outdoor +100' offers – the outdoor unit is not optional on a 3+ year-old unit.
Prevention
Both units yearly; the indoor one for your lungs, the outdoor one for your bill.
When to call us
0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; Aviației is close.
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Sources (4)
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.