Cooker extraction hood - vent 150 mm to 100 mm

[mointainwalker]

Hi

In preparation for my kitchen in my barn renovation I fitted a 100 mm PVC pipe behind the stud wall to take the exhaust from the cooker ( this some months ago ).

Not being too smart, I didn't confirm general vent sizes believing it would be 100 mm. Surprise for me, when I come to buy one, 150 mm is near universal here in France.

I haven't chosen an extractor yet but guess it will be a 3-speed 450-600 m3/hr unit, Run will be 90 o bend, 3m straight, 90 o bend, 1 m straight, 90 o bend to outside ( could leave it 3m straight if essential, but wanting to keep vent away from neighbours )

Moving wall for 150 mm pipe = significant work but will do if essential, but my question is, how much extra noise will be created by reducing from 150 mm in hood to 100 mm in pipe.

Haven't had one of these before so have no point of reference on noise front, except that I will exert myself to try and avoid it .

Any other comments on hood sizing/whatever welcome.

Thanks.

 

[Burnerman]

I know that reducers from 125 to 100mm are available here, but I've never come across a 150mm one. However, there may be something suitable in drainage fittings.
Is there any mileage in getting a UK spec extractor, and shipping it out?
Either way, I wouldn't suspect any dramatic noise issue, but thats purely a guess based on nothing.
John