Extractor fan ducting

[Fingerscrossed4]

Help!
Having a new kitchen put in with a fancy extractor fan over the island. Our kitchen designer has said that it must have rigid ducting as that works far better. Our builder says that we can go for rigid but it will need to have 4 almost 90 degree turns in it and therefore flexible ducting would be much better.
Anyone have any thoughts or experience of this? Need to give answer in the next couple of hours.
Thanks so much

Rigid with 4 smooth 90 deg bends is miles better than flexi. Builders like flexi because its easy to do. It doesnt work.

If you have a good quality extractor, look at Naber ducting systems and install 6 inch channel ducting and you will be fine. How far is it going and what is the extraction rate?

Listen to your kitchen designer. He probably is going to have best performance of your kitchen at heart.

flexi is very prone to drooping and sagging, and it captures dirt, dust, fluff and grease which is pretty well impossible to clean out, because it is ridged. In some conditions (mostly in cold lofts) it also accumulates condensation which lies in pools in the sags.

Rigid is far superior. It is less prone to dirt, since it is hard and smooth, can easily be painted to match your ceiling or walls if it is exposed, and is a bit quieter. You can usually run it with a slight fall so that any condensation runs to the outside and does not accumulate.

I expect they will use swept elbows rather than right-angles. It is much the same as soil pipe, so any builder or plumber knows how to cut and joint it (soil pipe is often used instead of duct, it can be cheaper and a bit thicker and stronger).

Yes, flexi is easier to shove into place.

Great thank you! Xx

For optimum performance ...... allow a reduction in total length of your ducting of 1-1.2m PER bend. Maximum reco length is 5m. This is for optimum performance. I reco Rigid / semi rigid with internal veins to assist airflow. Also use Naber ducting.

Anyone advise on the best place to by Naber ATM please?? Pigletjohn?

many thanks

If trade, buy through Hafele