Hi All,

The roof in our 2,750 ft2 office is leaking. Since it's rainy season here
in climate zone 4, we're trying to get it repaired quickly. We've decided
to add R19 poly-iso nail base to the un-insulated roof. There is an option
to install R26 instead.

I just started digging into the commercial building tax deduction (section
1331 of HR6) to see if R26 will qualify for the $0.60 or even the $1.80/ft2
deductions. I've created a model of the existing building in eQuest 3.64.
Given my modeling experience, there is not enough time to build a ASHRAE
90.1 - 2001 compliant model in version 3.63 to compare the energy savings of
R26 v. the baseline R15. Is there an outside chance that R26, being > 50%
better, would result in a 50% reduction in energy use? Is there a chance it
would result in a 16 2/3 reduction? I realize these may be tricky
questions, any thoughts are appreciated; disclaimers are ok too.

Thanks,
Justin

Justin Tiedemann, LEED AP BD+C