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Ducted unit hidden in the false ceiling — can it be sanitised without breaking into the ceiling?

Editorial guide · Updated 18 September 2026

In short Short answer: if the access hatches reach the evaporator and pan (not just the filter), yes, it can be sanitised properly through them — we access via the hatches, fit a sealed collection bag inside and pressure-wash through the available opening; if the hatches are too small or missing, cleaning is limited to the grilles and filter, and at some point the evaporator would need an installer to add another hatch, not an ad-hoc hole in the ceiling.

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

We have a ducted unit (Daikin, 18,000 BTU) fully hidden in the false ceiling in a renovated flat in Aviației; only the supply and return grilles are visible, the rest is under drywall. The builder left two small access hatches. Can sanitising be done without breaking into the ceiling, or do we need to call whoever installed the unit?

Editorial explanation · Revizie AC

What is really happening

Distinct bacterial communities develop separately on each component of an air conditioner — which is why every part must be cleaned individually, not just the accessible surface; on a ducted unit, if only the grilles get cleaned and the evaporator goes untreated for years, the condensate pan carries the same risk as on any other unit type — the highest bacterial load of any component in a residential split.

Explanatory diagramDucted system: airflow and access
Ducted system: airflow and access
  1. The return grille routes air toward the filter.
  2. The unit connects to air ducts.
  3. Grilles distribute air; the service hatch must stay accessible.
What the studies say
  • Air conditioners in Japanese homes host distinct bacterial communities on each component, showing that every part must be cleaned separately. [CORE (open access repository), 2015]
  • The condensate pan of household units had the highest bacterial load (~12,300 CFU/cm²), over 20 times the 500 CFU/cm² limit for public spaces. [Frontiers in Public Health / PubMed Cent, 2024]
  • The blower (cross-flow fan) is the most fungus-contaminated component of a split unit, more than the filter or the front of the evaporator. [Indoor Air, 2023]

What we do on site

  1. We first assess the existing hatches: if they reach the evaporator and pan, we fit a sealed collection bag through the opening, alkaline detergent, adjustable pressure wash adapted to the access angle.
  2. Supply and return grilles are removed separately, washed and refitted.
  3. Filters (if at the grille or hatch) are cleaned; fragrance-free sanitising of accessible components.
  4. If the hatches don't reach the evaporator, we tell you plainly what we could and couldn't do, without charging as for a full sanitising.
  5. See current rates on the Prices page.

What you can do yourself

  • Filters accessible through the hatch, every two weeks.
  • If you renovate again, ask the installer for at least a 40x40 cm hatch near the evaporator — it makes a difference at every future sanitising.

What NOT to do

  • Do not let anyone break into the false ceiling without first talking to the builder/installer who fitted it.
  • Do not pay full sanitising price if real access is only to the grille and filter.

Prevention

Ducted unit: sanitised through the access hatches if they reach the evaporator; otherwise, only grilles and filter, with a recommendation for an extra hatch.

When to call us

0764 012 943, WhatsApp, Monday–Saturday 08:00–20:00; send us a photo of the existing hatches before the visit.

Sanitising the unit in a boutique hotel room with cover and pump
Sanitising the unit in a boutique hotel room with cover and pump
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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.