Hob Extractor Ducting

GodlikeRed

Hi,

I'm currently in the middle of a build and are looking to install a downdraft hob.

There are two options for the extractor, ducting to the outside and recirculation (filters etc).

My preference is to go for venting to the outside but my builder has mentioned a few times this could impact the BER rating.

Can I still go for external venting and reach the intended A2 rating?

Planned specs (if this makes sense)

Target is A2, 200mm cavity (ecobead), underfloor, triple glazed windows, mech heat recover etc.

thanks,

Biker1

https://www.boards.ie/discussion/2058211509/hob-extractor-ducting

Your builder is incorrect, you can duct to the outside without having much effect on the BER. If in doubt get whoever done the provisional BER to check if it's ok. (That is if one was done)

ec_pc

We have external kitchen extractor vent, A2 rating.

GodlikeRed

I dug out the part L spec, the initial calculation was 49kWh/m2 /yr.....just about sub 50, very convenient - but there has been some changes since then.

I'll chat to the assessor.

thanks all!

Yellow_Fern

https://www.boards.ie/discussion/comment/117971798#Comment_117971798

Leaving aside the BER, in real world terms, extracts to the outside would have a significant effect on a houses warmth.

MicktheMan

https://www.boards.ie/discussion/comment/118034351#Comment_118034351

No, not necessarily. Take a reasonably airtight house with an external extractor over the hob. Turn it on and crack open a window close by to supply the air for the extractor. This is what we do and results in no impact on the rest of the house.

Yellow_Fern

https://www.boards.ie/discussion/comment/118051534#Comment_118051534

So basically use it not all day long and have very good detailing on the extract so there is no leaks?