MVHR proposed layout - looking for advice.

[Eric]

Here is an MVHR layout that I have received, I would like any feedback if possible. New 1.75, 375m2 build.

I think the lounge should just have 1 terminal with double pipe.

No terminals in the hall.

The extracts in the kitchen should both be double pipe.

Bedroom 1 has a vaulted ceiling so would prefer just 1 terminal for this also.

 

edit, all of the first floor are JJI joists, the kitchen/family room have had access hoses cut in them prior to installation as they are 400mm centres.

Edited December 4, 2022 by Eric

[Bonner]

As a 1.75, have you not got a loft space? Mine is very similar, just one pair of 150mm risers to the roof space and distribution to beds and baths from above. I would not be happy with all those pipes going up the walls. Even if you can hide them, it’s a potential noise issue.

[Nickfromwales]

1 hour ago, Bonner said:

I would not be happy with all those pipes going up the walls. Even if you can hide them, it’s a potential noise issue.

The ducts are silent, with the only audibility ever being at the terminals in the rooms, and that’s only if it’s been designed poorly / with bean-counting. I use radial MVHR distribution for every single M&E project of mine, as the results are excellent each and every time. 
Larger bore primary ducts off series arrangements have much higher airflow, so would be the more problematic afaic.

[Nickfromwales]

12 hours ago, Eric said:

I think the lounge should just have 1 terminal with double pipe.

No terminals in the hall.

The extracts in the kitchen should both be double pipe.

Bedroom 1 has a vaulted ceiling so would prefer just 1 terminal for this also.

Lounge yes, 1 terminal opposite corner to the door 

Agree on hall, maybe retain one?

Kitchen defo, not for airflow but to keep things quiet on boost. 
I’d stick with 2 terminals in the bedroom for the least amount of audibility, but you could go at the head of the ceiling and do as you suggest.

[MikeSharp01]

38 minutes ago, Nickfromwales said:

Larger bore primary ducts off series arrangements have much higher airflow, so would be the more problematic afaic.

Not sure I get this do you mean taking large bores off manifolds to higher manifolds is a problem and if so why are higher volumes more problematic is it to do with velocity in larger diameter ducts?

[Nickfromwales]

6 hours ago, MikeSharp01 said:

Not sure I get this do you mean taking large bores off manifolds to higher manifolds is a problem and if so why are higher volumes more problematic is it to do with velocity in larger diameter ducts?

Higher velocity at the larger bore ducting, ergo the terminals coming off those primary runs from the machine have to be strangled back more which tends to make them ( albeit slightly) more audible, particularly when boosting. 
Also means you can’t target specific rooms or floors when tempering the air via an air handling unit. For 2 current Passive House clients, I have specified Brink Air Comfort units to provide heating / cooling to 1st floor rooms where there is no wet space heating. GF cooling is via slab cooling, FF tempering is via the BAC unit so thus requires segregation at the plant and radial runs to rooms as per my designs. Large bore series run systems do not allow that flexibility, so whatever goes in at the plant goes to every room. 

[Eric]

12 hours ago, Nickfromwales said:

Lounge yes, 1 terminal opposite corner to the door 

Agree on hall, maybe retain one?

Kitchen defo, not for airflow but to keep things quiet on boost. 
I’d stick with 2 terminals in the bedroom for the least amount of audibility, but you could go at the head of the ceiling and do as you suggest.

Thanks @Nickfromwales

For bedroom 1 if I was to have 2 terminals would you suggest single or double runs for these or as the drawing, 1 double & 1 single?

[Eric]

14 hours ago, Bonner said:

As a 1.75, have you not got a loft space? Mine is very similar, just one pair of 150mm risers to the roof space and distribution to beds and baths from above. I would not be happy with all those pipes going up the walls. Even if you can hide them, it’s a potential noise issue.

I will have loft space but would rather have less of the ducting in the cold loft, just personal preference.

[Nickfromwales]

12 hours ago, Eric said:

Thanks @Nickfromwales

For bedroom 1 if I was to have 2 terminals would you suggest single or double runs for these or as the drawing, 1 double & 1 single?

In the bedrooms I go a bit OTT, as once this is in it is in for good. So I would do 1x duct to 1x terminal ( x2 ) in there. Sleep is precious, so is sanity. I would not bust this down to 2x ducts to 1x terminal ( x1 ) in there as the flow rates will be a bit higher in there due to the volume of the room.

[JohnMo]

For our master I did similar, one supply in bedroom 35m3/h, but a second one in a wardrobe/dressing room, think it was 15m3/h.  Extract in ensuite set at 35 m3/h, so supply air over and above 35m3/h has to travel through the rest of the bedroom and down corridor to the next extract point, keeping the corridor supplied with fresh air also.

[JohnMo]

Comments on your layout

Utility, very short run from manifold, not high flow rates, so not sure you require a double duct run.  Similar comment to other extract duct runs.

 

You could shorten supply duct runs everywhere by using coanda effect supply nozzles, these are wall mounted instead of ceiling, and the air will move across a ceiling for 4-6m, before dropping and then traveling across the room towards an extract. Something like these 

https://www.epicair.co.uk/collections/plastic-flat/products/supply-air-valve-coanda-effect-8960-90mm

 

You seem to doubled up extract ducts, but supply runs seem longer and are single duct, so this needs sorting out.