I was wondering if anyone has any recommendations on how to model an
eco-roof. How are the U-values / R-values determined? Are there any
standards referenced or typical assumptions made? Are there substantial
energy savings associated with a eco-roof?

I've read a few studies that claim that there are and are not
significant energy savings associated with an eco-roof, and I was under
the impression that the major benefit of an eco-roof is storm water
mitigation and possible sewage savings. I was hoping that the bldg-sim
group can shed some light on this topic. The projects I'm working on are
typically in the Pacific NW, where I would think the energy savings
associated with this technology would be minimal since the climate is
fairly temperate. I would appreciate any thoughts you might have on
this technology, it's associated energy savings and modelling
assumptions.

Thanks,

Erin