The homes I have seen this install in are mostly several years old.
No problems from the install, while I have not measured with a flow hood to
determine the air flow per room, no complaints in these well used homes.
Several new homes seek to incorperate this install, but it has to be incorperated
in the design phase. Very few homes not designed with a central to all rooms
area can make this work.
There have been 2 new homes that incorperated the fur down hallway,
both were commercial ac company owners. Both did the fur down without
ductwork, have low utility costs, enhanced hvac performance, and no issues
of condensation or mold.
If I didn't make myself clear...foam boards of any kind can not be used in this application. My understanding is that in the heating season that foam will offgas.Use only materials made for hvac..in this case, ductboard & mastic. It just makes sense.
I do agree that if the ductboard was installed with insulation facing out, that this would
be the correct install. sealing the foil faced sections of ductboard would be easy, and
you would not (or I would not) worry with the issue of particles of ductboard insulation entering the home.
Transfer grills can be offset with in the same wall cavity..one side 6" lower than the other to lessen sounds from passing thru the grill. Sound moves in straight lines, if you
can make it turn, it lessens the sound. (I'm sure there is a more professional way to phrase this!)
There are lots of ways to build the semi conditioned attic. Foam insulation being the easiest. I won't get into the issues I have with foam insulation, but lets keep talking about alternate routes to achieve the same result.
After hurricane Katrina I was in New Orleans to 'oversee' a slate roof replacement.
Ended up working the install also due to lack of skilled workers and the language barrier..
what we did was to remove the old slate..and an interesting thing was that the rear of the roof was not slate, but asbestos siding sections..
removed old slate, cleaned & stacked for re-install on rear/back section of roof
installed roofing membrane,
installed 1" polysyrene foil sheating boards, foil facing up
on top of foil boards 1" furring strips
layer of plywood
and then slates.
the edges of the roof were sealed air tight.
This install is called 'ice house roof'
It performed as a radiant barrier with the air space
unvented roof because of the sealing of the edges.
In this cottage attic space was turned into a guest suite and the
peak was not acessable to add additional insulation.
the eaves of this guest suite was storage and we spent
an addtional day caulking and sealing storage areas.
The complaint for the guest suite was that in august sept that it
was unberably hot. Now it stays an even temp year round.
Lots of ways to achive the same result.