MVHR - critique my plans & 3 blockers left

[Sparrowhawk]

Having got stuck with how to route the MVHR ducting for my retrofit, I've spent the last few months sourcing design quotes as it's getting beyond me and I wanted to get a pro's input. After being quoted £750-£1000 for design-only without them even glancing at the brief or plans I submitted, and then warning that "If it's more complex than we expect that'll increase" I'm back to trying to sort the blockers myself.

 

Through false ceilings in the landing, a side room and part of the dining room I've managed to keep the ducts out of the cold loft and within the thermal envelope. I've got access to almost all rooms without little visible boxing in. But I have 3 remaining problems:

 

1. First floor: how to get ducts from the landing to bedroom 2 / en-suite /wardrobe. There's a disused chimney breast in the way, plus the ceilings in the extension are lower. This is where I gave up last time and went looking for an expert. If it was 1-2 ducts I'd say core drilling, but there's 3, or 4 if the en-suite needs doubling up. Swiss cheese anyone?
    
2. Linking the ground and first floors. My current idea is to take down the lathe and plaster wall between the landing and bedroom 4 and build a new wider wall with the ducting inside it.
    
3. The 70cm wide loft hatch (not shown on plan) is smack bang in the middle of the landing corridor and I overlooked it. Short of making it narrower not sure how to get the ducts past it.

 

What do you think?
 

I'm also uncertain about the supply/extract vent positions. Upstairs they'll have to be in the wall not ceiling so I don't break through into the cold loft; and few are at the correct point in the room. Will coanda effect vents do enough to circulate the air when wall mounted?

MVHR plans anonymised.pdf

[Redbeard]

As ever I shall deal with the easy ones first: Move the loft hatch: Sorted.

 

You also said:

15 hours ago, Sparrowhawk said:

I've managed to keep the ducts out of the cold loft and within the thermal envelope.

 ...which is good. However you have a chimney breast in the way. Why not run the ducts above the ceiling in the void (*very well-insulated*, of course) and, with some 45 degree bends you can dodge round the ch. breast: Sorted (??)

 

15 hours ago, Sparrowhawk said:

•  
• Linking the ground and first floors. My current idea is to take down the lathe and plaster wall between the landing and bedroom 4 and build a new wider wall with the ducting inside it.
   

 

Very sensible plan. I don't have a better idea than that.