MVHR in Vaulted area, Extract or Input?

[FreddyK]

Hi,

 

I am in the middle of house renovation / extension and putting in Ducts to enable MVHR installation at a later stage. Using a design by Bpc and installing myself with help of non specialist contractor. There was one question the  Bpc designer was ambivalent about.

 

The open plan living / kitchen area has two fresh air inputs on the sitting area on left side and two extracts on the kitchen area on the right side. There is a vaulted ceiling area that protrudes towards the garden and has a lot of glazing.  I can run ducts to the apex of the vaulted ceiling. Should this be an extract to get out all the hot air in the summer (I am concerned it will get too hot in there with a lot of glazing and velux windows) or should it be an air input (which is what Bpc originally suggested and I am concerned if it is an extract it will be too close to the sitting area inputs and will short circuit them). 

 

See drawings attached for both options.

 

Appreciate your advice.

 

FK

 

 

[Nickfromwales]

Fresh air, definitely. Just commissioned one almost exactly like this, and fresh went into the dining and vaulted area feeding back towards the kitchen. This ensured the glazed area would never get 'stuffy' and the smells from cooking would never be attracted towards these areas.

The design should be adapted to have the "UNIT2" fresh nearest the vaulted area moved to be in the vaulted area, with both of those spaces then having a single ceiling valve which has 2x ducts to each giving fresh air in.

NOTE: extract will shift bugger all heat from that glazed aspect  Trickle rates just do not shift anywhere near enough air to even scratch the surface. 

[MikeGrahamT21]

Yeah seconded, definitely supply. The slightly cooler air will then drop down into the room from the vaulted space, and will give positive pressure, meaning, as nick has said, the smells from cooking would be pushed away from the area.

[FreddyK]

Many thanks Nick and Mike. Very useful

response. FK