Cooker Hood Ducting Sizes

[Pemu]

Hi

I'm trying to work out which cooker hood to get and also make sure I have the right wiring/ducting planned beforehand. 

I want a powerful one as my previous one wasn't too good at getting rid of the stone curry smells our cooking produces. 
I have read mention online of the more powerful ones requiring 6" or 150mm ducting which makes sense but I was struggling to find the information I need on websites like Screwfix and AO. The listing don't say what the exhaust looks like and what size ducting is needed. 

I've currently got a 4" / 100m hole and I need to know if the type I need would need a larger hole and then I'd have to plan to enlarge that and so on. 

 

Any general advice in the topic would also be helpful.

[nod]

I’ve fitting ours this morning Prior to the quarts arriving 

Nearly all specify 6” 150 ducting Our previous Italian extractor stated that the warranty would be voided for anything less 

[Barnboy]

Our kitchen designer recommended I put in a 6"  duct before we'd even got a design from him, more on the basis of you'll get less noise from a 6" than a 4".

When our kitchen arrived the hood came with a 6"-4" reducer so could have been fitted either way but why would you want to pump a 6" capacity fan into a 4" hole and choke it.

I'd put 6" in if I was you, it's always better to go bigger and be safe.

 

[JohnMo]

10 hours ago, Pemu said:

want a powerful one as my previous one wasn't too good at getting rid of the stone curry smells our cooking produces

The most important but you are missing, is the distance from the hob to the extractor. The larger the distance the more useless the extract becomes. Most installer just do what they have always done, you need to read the manual then insist the installer sets the height correctly to the minimum height for your hob type.

[Pemu]

Thanks for all that. I guess that might explain why the current one is not very effective despite being so loud. 

 

So would I be right to assume that the powerful ones, by default, have 6" exhausts which is why they don't mention anything specific about it in the listings and drawings?

 

I guess that means I'll have to buy a 6" core drill. I hate to think how much that's gonna be.

[JohnMo]

32 minutes ago, Pemu said:

guess that means I'll have to buy a 6" core dril

Or rent?

[nod]

56 minutes ago, JohnMo said:

The most important but you are missing, is the distance from the hob to the extractor. The larger the distance the more useless the extract becomes. Most installer just do what they have always done, you need to read the manual then insist the installer sets the height correctly to the minimum height for your hob type.

Exactly 

Shortest possible 

[Lofty718]

https://www.appliancesuperstore.co.uk/fisher--paykel-hp90ihcb3-90cm-built-in-extractor-hood-8578-p.asp

 

 

I've got this, running up a chimney flu with 150mm ducting, it is very powerful

 

Builder initially ignored instructions and put in 100mm ducting, but I ripped it out

[bassanclan]

1 hour ago, JohnMo said:

Or rent?

Or just use whatever long SDS drill bits you have and lattice a 6" hole. It would be done before you got back from the hire shop!

[Canski]

I recently installed a 150 duct with an erbauer core bit from screw fix. It went through fine. Jeez that fan sucks. You could dry your hair under the cooker hood. Mine also came with a 150 tip 100 reducer and I’m glad I tossed it away and went full bore.