I have an existing IXL (Heat, light and Fan) setup in a small bathroom (12.14 meters cubed). The air exchange rating of the fan meets the spec required for the room, it works and doesn't look that old. I have held a piece of toilet paper up to the fan (with the lamps taken out) and it seems to get sucked so it suggests the fan is sucking air. I took it out of the ceiling to look around for obstructions but nothing seems in the way between the outlet vent of the fan and the roof vent which is situated above the fan (it's a flat roof, so no attic space.

My question is does there need to be ducting between the fan and the roof vent ? The amount of space where the outlet vent feeds to is only a basketball or two in space (before there is insulation), however there is a path for the air to then go up the roof vent (though the path is not direct).

Also, just in terms of safety, whilst up there the cover to where the wires all fit in came off when lowering the fan - I have just put them back without putting the cover back on as this was getting too difficult and awkward to do. does anyone know if this is reason to be concerned?


Insulation space where fan vent points

Cover where wires and connections are

Picture of Fan enclosed in casing

Difference between clean and uncleaned fan blades

1 Answer 1


There should be ducting the entire way. As it is moisture is able to collect on your insulation, lumber, etc. This can result in mold and rot.

That said, I doubt that your exhaust venting will be improved by installing full ducting. If airflow is poor it's likely due to a crudded up fan or weak fan motor. Check the fan for collected lint. Clean it thoroughly. You can often remove the fan cage and wash it separately with water.

Yes, the electrical connections must be in an approved, enclosed junction box. Should anything go awry the compartment can help contain sources of fire.

  • Looks like that second pic is just open to the sky....
    – gnicko
    Commented Jul 2, 2019 at 16:17
  • It's an illusion due to limited photographic exposure range. Also, "... between the fan and the roof vent".
    – isherwood
    Commented Jul 2, 2019 at 16:33
  • Ducting would be difficult to install as this particular Fan has the outlet out to the side, and the roof vent is directly above. Given what you said, it seems probable that it is a weak Fan motor, as when I took a look the fan looked quite clean (adding another photo to the post). I think the best approach then might be to get a new unit and test, as that will tell me if it is the motor or not. I did find another brand (IXL) have a unit with the same function and the fan extracts to directly above the unit - this would also alleviate the moisture on insulation/lumber risk
    – Chris T
    Commented Jul 4, 2019 at 0:14
  • Regarding the picture of the roof vent, correct it is an illusion due to the automatic exposure of the camera
    – Chris T
    Commented Jul 4, 2019 at 0:15
  • As isherwood mentioned cleaning did improve airflow. The fan blades were crudded up with a layer of lint. I thought that initially the colour of the fan blades were a grey, though after some wiping with cotton buds I soon found out they were actually white! Even though I gave them a good clean, the performance still doesn't do the job. So it must be a weak motor, or other factors in the room that prevent it from effectively venting the steam out
    – Chris T
    Commented Jul 8, 2019 at 11:02

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