Extractor ducting - pinch point

[StixxUK]

Hi,

I've recently had some building work done - all really good and super happy with it all.

We have one problem we're now trying to find a solution for which is that the kitchen extractor is far louder than it should be.

The extractor is over an island, and goes through the ceiling to a chimney on a flat roof. 2 90 degree bends and probably most problematic, it has to pass through a massive steel beam - which has a hole cut in but could only make this wide enough for some 100mm ducting.

Question is - being fully aware none of this is ideal - if we had 6 inch ducting either side with only a small pinch point through the steel, is that materially better for noise and airflow than having 100mm all the way through, or is it only ever as good as the smallest point?

I know the best answer is rigid 6 inch ducting all the way, but it's not possible - the only other option is recirculation.

 

[foxhole]

Mines all 100mm , through the ceiling can be also especially noisy because of the large area which can amplify the noise.

 

[dontbelieveawordofit]

you cut a hole in the beam ?

 

[StixxUK]

Well, we had it cut by the beam manufacturer (having been specced out by the structural engineer)

 

[Burnerman]

My Zanussi extractor is nicely quiet on its lowest setting.
My other Howdens extractor is bloody deafening by comparison.
Both have the same size flexible ducting.....maybe its to do with the appliance?
John

 

[StixxUK]

Could be, I think it is fairly powerful, but when we disconnected the duct it's pretty quiet.

Maybe a weaker fan would be quieter but also wouldn't do as good a job. I think what I've learned is you've a choice between a great extractor setup and having the hob wherever you want... And the two may not be 100% compatible!

 

[JohnD]

the kitchen extractor is far louder than it should be.

You haven't told us which extractor you have got. They vary.