Building simulations for EPACT credits require that the building energy
and power costs be reduced by 50%. The tax credit has been extended to
2013.

The energy and power cost savings must come from a 16-2/3% reduction in
three categories: Building envelope, HVAC and SHW, and Lighting. There
is a guideline called "Energy Savings Modeling and Inspection
Guidelines for Commercial Building Federal Tax Deductions" Second
Edition, which is Technical Report NREL/TP-550-40467, May 2007.

In this guideline, they describe the technique on pages 3 and 4 to
calculate the costs and % cost reductions due to the Lighting, and
HVAC/DHW electricity use. Nowhere does it describe how they want you to
calculate the cost and cost reductions due to the building envelope,
despite the fact that 16-2/3% of the energy savings are required to come
from this category.

Does anybody know what to do for the building envelope and the EPACT
deduction?

Has anyone seen a spreadsheet available already created to do the cost
allocations based on the outputs from a simulation program (in my case
Trane Trace 700)? There are quite a few available for the simple
"Interim Lighting Rule" but none that I have found for the full model.

Also, in April 2008, an IRS Notice 2008-40 called "Amplification of
Notice 2006-52" describes being allowed to change the portion of the
savings for the building envelope to 10% if the Lighting and HVAC/DHW
savings are increased to 20% each (for a total remaining at 50% energy
and power cost reduction).

Has anybody seen this used? I have searched around for examples of
EPACT and all places still reference the 16-2/3% thresholds.

Nick Anderson