Kitchen cooker hood: recirculating or with long extraction duct?

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I'm getting a new kitchen and I need to buy a new cooker hood.
I would like to get one I can use with a duct to actually take fumes (and especially moisture) out of the house, but I'm worried about the long run drawn in yellow in the picture (as it would have to cross the utility room since it's a terraced house).

Is it possible to do or should I just get a recirculating one?
 

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Hi,
Do the run! :)
Its really not that long, and the benefits will far outweigh any construction hassle.
A recirculating fan will do nothing for condensation in your enclosed kitchen.
It would be best to use some rigid ducting.
If you need something less obtrusive than a large circular pipe, rectangular duct work is a good alternative.
 
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100% do the run. I just did a 4.5m run with the rigid aluminium ducting and it works great.
 
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Definitely duct to the outside.

I would be tempted to use an line extractor fan in the duct run where it goes through the utility room to create a greater flow and reduce the noise created in the kitchen.

Ensure there is a way for replacement air to get into the kitchen ( gap under a door ) to replace the air that has been extracted
 
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Could I go up as soon as I get into the utility (there is nothing above, just a flat roof)? If I do the run the the utility outside wall I would end up just above the boiler's flue, I don't suppose this would be a problem either?
 

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Yep, run it. I have a bit of drainage pipe for a 5m run, seems to do the job.
 
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Could I go up as soon as I get into the utility

Moisture condensing in the vertical section would have no way to drain out of the duct.

There are regulation about minimum distances between a gas boiler flue and other ducting
 
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Worcester Bosch recommendations for distances attached.

300 mm clearance to horizontal air vent required.

Some of your other clearances might be a bit close as well! :)
 

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Worcester Bosch recommendations for distances attached.

300 mm clearance to horizontal air vent required.

Some of your other clearances might be a bit close as well! :)

Can I just extend the boiler flue with a 90 deg bend upwards so it’s 30 cm away from where I want the extractor duct (roughly where the gutter is now)?
 
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Recirculating hoods are rather pointless, find a way to duct it outdoors. Don't use flexible ducting, that would reduce the effective flow/offer back pressure, and slope it slightly down to the outside to promote drainage out, rather than in of condensation.
 
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roofs are meant to keep the rain out, so making a hole in yours might have undesirable effects.

If you use rectangular duct, up against the ceiling, amd paint it to match, it will not look obtrusive, especially if you have wall cabinets or even shelves.

You can use an elbow to take the exit point of the duct away from the boiler flue, I bet it will be cheaper and easier.
 
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When I did my ducting, I used a cut down end panel that matched the kitchen.
I cut it to about 200mm wide with the finished edge outwards, horizontal about 200mm below the ceiling.
The duct sits inside and is boxed in with painted ply to match the walls.
It also acts as a handy route for some cables.
 
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I am looking at 204mmx60mm rectangular ducting and they only come in 1m lenghts which means having a lot of joints
If every connection needs a joint it means that’s a potential point of stagnation for condensed water, any tips?

As my outside wall is rendered is it worth putting a rectangular vent or should I just convert back to circular and cut a circular hole (which is easier than trying to guess where a brick is to install an airbrick type of vent)?
 
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