MVHR in plant room outside thermal envelope?

[Weebles]

Anyone built a plant room outside the thermal envelope of a semi-passive house?  Our design currently has a bolt on plant room and we are wondering whether the MVHR will work OK in there and whether the plant room needs to be as insulated as the rest of the house.  Other stuff going in there include gas boiler / hot water cylinder / ufh manifold.  Planning on MBC timber frame......

Got planning permission last week but already looking at a couple of variations so might as well do them all in one go.

[MikeSharp01]

I think @recoveringacademic is doing something like this is the link. 

[Weebles]

Our plant room will be adjacent to the house i.e. they will share a wall (possibly a very well insulated one) so I don't have the issues of considering running ducting underground.  But if we put the plant room outside the thermal envelope it will be colder than the rest of the house.  Will this temperature differential be a problem as the MVHR unit will be in the colder plant room (inlet and outlet pipes going outside from that room) and then the ducts will run across the colder plant room into the warmer house, presumably losing heat as they go back.....  Ah, does that make my situation just like @recoveringacademic .....?

[PeterW]

You will be fine as that plant room will be warm anyway ..! Insulate it well as tanks and boilers lose heat quickly. 

 

The new MVHR units are designed for cold roof spaces so as long as your main ducts are insulated - to stop condensation mainly - then you will be fine. 

[Weebles]

Thanks PeterW.  No change to plans needed for that then.  We will make sure we insulate the plant room.