We have recently moved into a first floor apartment in a new building that is approximately 9 months old. We are finding that we are absolutely plagued by a constant layer of dust building up in each room, regardless of the extent that the room is used.

The home is fitted with a Nuaire MRXBOX (MVHR ECO - ECO2) which is connected by ducting to a ceiling vent in every room (two in the larger rooms) with the exception of the entry hallway.

I dusted, hoovered, and mopped each room 2 days ago and there is already a thick, visible layer of dust everywhere except the hallway (which doesn't have a ceiling duct). The dust appears to be distributed fairly evenly throughout the surfaces and skirting boards of each affected room.

We open all the windows most days as it is typically warm here. We close all windows at night.

I have some questions about the MRXBOX:

  1. Is this unit likely to be responsible for the continual flow of dust into each room with a vent?
  2. If so, is there anything I can do to reduce the amount of dust coming from the vent?
  3. Are there any negative effects of disabling the unit (i.e. powering it off)?
  • 2
    Duct cleaning should be done after construction. Usually it is owner responsibility.
    – user263983
    Sep 5 '21 at 21:04
  • 2
    A gap in the inlet tubing, so inlet air is taken from the dusty ceiling space Sep 6 '21 at 0:45
  • 1
    You could put something in front a a vent to test what is coming out. Something fibrous like polyester stuffing, or even just a piece of fabric taped on 3 sides around the duct. You could get some liquid soap on these things before you put them up to make them sticky. If they are loaded with dust in 2 days then the dust is coming from the vent. If not maybe the dust is coming thru your windows.
    – Willk
    Sep 6 '21 at 16:19
  • @Willk Thank you for the suggestion. I'm going to do that to establish that it's definitely the vents causing the issue before taking any action to remedy anything.
    – Martin
    Sep 6 '21 at 18:53
  • Just a follow up to this to confirm that having conducted a remote inspection with the manufacturer, they have confirmed that there is a fault in the duct work supplying the home and an engineer is coming to investigate.
    – Martin
    Sep 13 '21 at 13:48

Make sure the filters were installed in the unit. They are sometimes left out during construction when the units are tested due to all the dust. they might have forgot to install them. If they are there, clean them or replace them. Not really a good idea to disable ventilation units.


If your ventilator is exhausting air from the apartment, then air (and dust) are being drawn in someplace. If the ventilator filters air and discharges it back into the apartment , it is not a problem.

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