MVHR Design with Loft Conversion

[malk]

Hi all,

 

Another ask for thoughts on MVHR design please. I've attached some general plans and am trying to work out what, if anything is feasible. We're really tight on room which obviously doesn't help and the isn't a great deal of height so the joist depth won't be massive. The proposed 2nd floor plan is all new work and we'll be getting a reroof at the same time. We've got initial plans but these can still be changed, e.g. currently the joists between 1st and 2nd floors are standard and could potentially be swapped for something like posi joists. The ceilings in beds 1 and 2 will be lowered.

 

But overall it's 9 rooms worth of ducting to run and I'm struggling to see how everything can fit in...

 

The main desire is for better air quality. At the moment we've got extract in the kitchen and bathroom but no trickle vents and the chimney is sealed (i.e. boarded over at ground floor level). Measuring C02 in Bed 1 and it can get to 2000 with 2 of us sleeping in there with the window closed at night. The House itself is a 1900s mid terrace, some insulated render on the external walls of the living room, bed 2 and bed 3. I can't imagine it's particularly airtight at the moment but it is really stuffy with the windows closed and keeping humidity under 70% is a struggle.

 

Part of me wonders if it would be worth just running extracts from bedrooms 1 and 2 and supplies to the living and dining room, supplies down through the chimney breasts, then supplementing with single room units in the annex section. Or decentralised everywhere. Or giving up completely and going with positive input or something else completely different.

 

Any advice/thoughts etc much appreciated!

[JohnMo]

I would

Supply to lounge, extract kitchen, use dining as a pass through area, the rest something like explained on the attached, almost no duct required.

 

615103-a-leaflet_multi_air_supply-en-dig-lr_5057512563596.pdf