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When is the best time to book sanitising – spring, summer or autumn?

Editorial guide · Updated 18 September 2026

In short Short answer: April–May is the ideal window – the unit is clean exactly when it starts condensing, bookings are available within 2–3 days and we work without heat on the balcony; the second good window is September–October, when you leave it clean for winter. July works, but with a wait and with the unit already two months dirty.

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.

Situation discussed

Rahova, block, two LG units. Last year I called in July and every company had a two-week wait. When is the 'right' season for sanitising, so I do not sit in a heatwave with a smelly unit?

Editorial explanation · Revizie AC

What is really happening

Biofilm grows in the cooling season, when the evaporator is wet; in winter, dry and cold, it stands still. So a clean in April gives you the longest period of clean air during the hours that matter; one in September spares you the spore 'burst' at the first start-up of the following year (starting a contaminated unit can multiply room spores tens of times). Both are correct; what is not ideal is waiting until it smells. Manufacturers, incidentally, recommend exactly drying on 'Fan' before the period of non-use – autumn is the natural 'closing' moment.

Explanatory diagramBefore-season preparation
Before-season preparation
  1. Read the manual and check accessible filters.
  2. Watch for leaks, unusual odours and noises.
  3. Request inspection if something is abnormal.
What the studies say
  • 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]
  • 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]
  • Manufacturers recommend running the unit in fan-only mode for several hours to dry the interior before long periods of non-use, precisely to prevent odour and mould. [Daikin Europe, 2020]
  • ASHRAE 62.1 requires visual inspection of cooling coils for cleanliness and microbial growth at least once a year and cleaning whenever fouling or microbial growth is observed. [ASHRAE, 2016]

What we do on site

  1. Booked in April–May (or September–October): both units in about 2.5 hours, at a fixed time.
  2. Full protocol on each: sealed double cover, alkaline detergent, adjustable pressure wash of evaporator, roller, pan and hose; sanitising; filters; outdoor unit in place.
  3. We note the same month next year in our calendar and call you – you skip the July queue.
  4. See current rates on the Prices page.

What you can do yourself

  • Put 'AC sanitising' in your phone for 15 April.
  • Autumn: filters washed, 2–3 hours on 'Fan', then off.

What NOT to do

  • Do not wait for the first heatwave to call – everyone calls then.
  • Do not switch it on in June 'to see if it smells' before cleaning – you air it of spores yourself.

Prevention

Yearly, in the same month, preferably April–May; in autumn only drying and filters.

When to call us

0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; in April we reach Rahova within 2–3 days.

Old outdoor unit covered in dust and dirt on the façade of a Bucharest apartment block
Old outdoor unit covered in dust and dirt on the façade of a Bucharest apartment block
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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.