timmmay:

 

tweake:

 

its not normal even in colder climates (using USA as an example, europe does things different but they also don't use a lot of ducted systems afaik). its relatively new especially as usa keeps pushing for more efficient houses. the joe blog usa house still runs ducts under the floor or in the ceiling outside of the insulation. they are leaning its better to put it all inside the envelope, something we could do without having the many many decades of putting ducts in ceilings.

 

the insulation goes right under the roof, just like any normal cathedral ceiling that many many nz homes have. basically the whole house has cathedral ceiling, even tho it also has a normal flat ceiling as well.

 

 

Ah ok. I watched quite a few videos from the US when I was getting my ducted system installed, they made it sound like it was normal. It would add a lot of area to be heated if the insulation is way up near the roof, it doesn't sound worthwhile. I wonder how it's done in the states, maybe a false ceiling or something, but I guess it'd have to be pretty extreme weather to be worth it.

 

My other thought, on a floor level return vent, may still be worthwhile. Or just avoid the ducted system.

 

My house in Dubai has the HVAC as part of the design with rigid ductwork inside the building fabric and the plant in the ceiling of bathrooms. It adds a considerable amount onto the stud height, they are all around 3.5 metres with false ceilings for the duct work. It makes sense here where the temperatures are more extreme, New Zealand is temperate so adding that much extra space onto the build doesn't make much sense.