Looking for bathroom fan/light unit with 200mm duct

Forums › Home Workshop DIY › Looking for bathroom fan/light unit with 200mm duct

cddt

1548 posts

Uber Geek

#319892 12-Jun-2025 07:49

The old unit was tripping the RCD, an electrician found water inside the fan housing. So we need a new one! But finding a suitable model is proving difficult.

We are looking for something with a 200mm duct (if possible).

The old one is a triangular shape, we don't care about the shape of the new one but it's easier to make an existing hole bigger than smaller. Current dimensions are about 310x240.

Any ideas of where to look or who we could speak to? Searching online hasn't been successful so far.

My referral links: BigPipe | Mercury

timmmay

20574 posts

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#3383072 12-Jun-2025 08:51

200mm is pretty large for a light / extractor combo. I put your question into Perplexity and found this option.

You could do this fairly easily with a dedicated fan from somewhere like Fantech or Smooth Air. Give them a call. Then have a couple of downlights put in if you need more lighting.

Bung

6477 posts

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Subscriber

#3383077 12-Jun-2025 09:17

Is 200mm duct size to match existing ducting?

Just wondering if that duct was oversized for the fan in your old unit. If the air is moving slower there might have been more water condensing on wall of duct and possibly running back into fan.

cddt

1548 posts

Uber Geek

#3383171 12-Jun-2025 12:48

timmmay:

200mm is pretty large for a light / extractor combo. I put your question into Perplexity and found this option.

You could do this fairly easily with a dedicated fan from somewhere like Fantech or Smooth Air. Give them a call. Then have a couple of downlights put in if you need more lighting.

Unfortunately that isn't ducting size, it's the light size, the ducting on that unit is 125mm.

The suggestion about a dedicated fan and then separate lights might have to be the way we go.

My referral links: BigPipe | Mercury

cddt

1548 posts

Uber Geek

#3383178 12-Jun-2025 13:16

Bung:

Is 200mm duct size to match existing ducting?

Just wondering if that duct was oversized for the fan in your old unit. If the air is moving slower there might have been more water condensing on wall of duct and possibly running back into fan.

Yes 200mm to match existing ducting.

Your suggestion about additional condensation aligns with my hypothesis - that the cold weather also increased condensation within the duct which ran back down into the fan housing.

My referral links: BigPipe | Mercury

timmmay

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#3383182 12-Jun-2025 13:48

Ah that's the whole thing diameter. I'd be surprised to find any integrated units with 200mm ducting. You could use an adapter, or the standalone fan is easy.

RunningMan

8953 posts

Uber Geek

#3383266 12-Jun-2025 17:08

Can you run a smaller diameter duct inside the existing one?

Nath5

4 posts

Wannabe Geek

#3383770 13-Jun-2025 20:16

You could use a duct reducer like one of these:

https://simx.co.nz/product-groups/grilles-diffusers-and-ducting/duct-fittings/duct-reducers

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cddt

1548 posts

Uber Geek

#3383837 14-Jun-2025 06:15

Thanks for the suggestions. My wife rang the company which made the current unit, it must be really old because they said they don't (and have never) made any unit with a 200mm duct... will try one of the suggestions above!

My referral links: BigPipe | Mercury