Is anybody's state or local building/energy code requiring them to use vapor barrier boxes for their new Resi construction?
These are the ones with the foam gasket around them to supposedly stop air transfer and save energy, like the T&B/Bowers FN series boxes.
Just wondering how much more expensive these are than standard boxes and if their benefit outweighs the additional cost.

TKX

not so much required as strongly suggested here via the energy efficency people within the state of Vt

no actual one product spec'd out, so i've used a can of spray foam bettween rock & paint to keep the peace....~S~

I thought for sure that either LEED or some state where or the energy aficionados were rampant would have mandated these boxes. Hopefully I haven't given them any ideas.

My state's building code addresses perforations for electrical outlet boxes on exterior walls, which basically requires the use of the foam sealing gaskets behind the wall plates for switches and receptacles on outside walls, but that is it as far as I know.
This doesn't seem to be enforced locally in all areas though. I always use the wall plate gaskets regardless, as they are not very expensive and it seems like a good idea to at least try and stop some air transfer, given the known leakage values through these areas.
I'm still kind of curious though as to how much, if any, improvement there would be if both the vapor barrier boxes and the foam wall plate gaskets were used together.

Nope can't say I've seen or heard anything about them.
When I built my house,I used caulk to seal the boxes on the exterior walls. I caulked the holes the cables entered the box and any unused "knockouts". I caulked any penetrations where a cable was stuck out through the sheathing also. I did all this prior to installing my insulation. I have no air leaking in through my receptacles and switches.

The Kentucky Residential Building Code, 2007 is silent on the issue.