Ducting for a cooker hood

Just done exactly the same thing, but haven't powered it up yet, so I hope it works! However, I used 150mm rectangular ducting from TLC because a) the hood instructions specified it and b) I would have anyway as you want to max out the extraction in a kitchen. There was a matching airbrick which I installed, although they do do the square vents and the one with the flaps. No idea which is better. Maybe someone has an opinion. If you can get away with one 90 degree turn at the top of the hood and then a straight run to the outside, this gives the best possible airflow.

Alistair

One good idea someone suggested to me was to run the ducting between the ceiling and the upstairs floor! Though it depends which way your joists go whether that is practical or not!

If it was hidden it would really matter what ducting you used.

I ran mine in a lowered ceiling - built to also even out the ceiling heights in a knocked-through dining-room/kitchen as well as to quickly solve the problem of what to do with the existing artex, ceiling downlights and fake beams!

This approach meant I could take full advantage of the 500m3/hr (freeflow) fan output by using 6" ducting consisting of a 4m run with a

A few photos if they're of any use/interest:

Mathew

Yeah, we did this with the screwfix kit - it was fine. Circular adaptor for the cooker hood, and then rect ducting on top of the wall units to the o/s wall, terminated with a downward pointing vent. The shape is good to hide away, and it goes through brickwork nicely (because you can rake/drill out the mortar courses and work with whole bricks). Good airflow, worked for >2yrs now.

Always seemed like a bodge to me, significantly less flow than the round stuff and almost guaranteed that the duct wouldn't line up with a single brick.

One slight problem I should have mentioned - I can't use the void between the ceiling and floor above (don't ask, but it's something to do with a really badly fitted bathroom floor)- which is why I like the idea of the rectangular ducting as it should look ok mounted on the ceiling.

Thanks for all the responses, I think I'll be ordering stuff from Screwfix.

Agreed. Always use round ducting if you can fit it in. Use as few bends as possible (avoid 90 degree bends).

Mark.

I'll admit we were lucky with position - the height was right, and the lateral could be adjusted an inch or two because it was out of sight on top of the cupboards. Can't really comment on peak airflow, but it amply copes with a £50 Comet hood.

^^^^^^^^^^^^^^

That'll be why it copes then...! ;-)

Mathew