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Why do you use two solutions? Isn't one 'disinfectant' enough?

Editorial guide · Updated 18 September 2026

In short Short answer: they do two different jobs – the first (alkaline) solution lifts biofilm, grease and dust off the aluminium so they can be washed away with water; the second (sanitising) is applied to the already-clean surface to delay recolonisation. A disinfectant on dirt does not penetrate biofilm, and a detergent does not sanitise; the order and the rinse between them are the essence of the method, not marketing.

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

Otopeni, house, 3 Daikin units. One company told me they use 'a single professional solution, disinfecting and degreasing at the same time', another that they use two, separately. What is the logic? Isn't it just marketing?

Editorial explanation · Revizie AC

What is really happening

Biofilm is a structure: microorganisms in a polysaccharide matrix glued to the metal. A disinfectant attacks the surface layer and the rest stays protected – which is why the EPA insists on physical removal and says biocides are not routine practice. The alkaline detergent breaks the matrix and saponifies grease; the jet carries it into the cover; only then does a sanitising solution have something to act on. '2-in-1' products compromise on both – they are usually no-rinse sprays that leave residue on the fins, onto which the next dust sticks.

Explanatory diagramA cleaning cover directs wash water to a container
A cleaning cover directs wash water to a container
  1. The area and sensitive components are protected before work.
  2. The cover collects wash water.
  3. The hose directs water into a container.
What the studies say
  • EPA principle: mould must be physically removed, not merely 'killed'; biocides are not recommended as routine practice. [US EPA, 2024]
  • EPA warns that the effectiveness of biocides sprayed into air systems has not been demonstrated and their health effects are uncertain. [US EPA, 2024]
  • Methylobacterium, the dominant bacterium in evaporator biofilm, is a strong biofilm former resistant to UV, desiccation and heat/cold shock. [mSphere (ASM) / PubMed Central, 2020]
  • 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

  1. On each unit: sealed double cover, hose to the bucket, foil.
  2. Solution 1 – alkaline detergent for aluminium coils: on evaporator, roller, pan; 5–10 minutes; adjustable pressure wash until the water runs clear (i.e. no detergent left on surfaces).
  3. Solution 2 – sanitising, chlorine-free and fragrance-free: on evaporator, roller, pan, louvres; left to act and dry.
  4. Filters washed; outdoor units washed in place (detergent and water only there – sanitising outdoors is pointless).
  5. Drying on 'Fan', test on each. See current rates on the Prices page.

What you can do yourself

  • Ask the 'single solution' company: is it rinsed with pressure water between application and finish? If not, it is a spray.

What NOT to do

  • Do not buy 'no-rinse sanitising'.
  • Do not mix products at home (bleach + acid = toxic gas).

Prevention

Yearly, with both stages; with '2-in-1' you end up paying twice a season.

When to call us

0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; Otopeni is in our area.

Sanitising the unit in the children's room, with cover and mask, toys in the background
Sanitising the unit in the children's room, with cover and mask, toys in the background
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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.