Nov./Dec. 2007

Lessons from the LEED Trenches

Beware of LEED Online Template Errors

Embedded Error Found in E&A Green Power Calculator Template

by Courtney France, President, France Sustainable Solutions

While recently calculating (or, in this case, actually estimating a project’s total Green Power contract cost) the total amount of Green Power required to achieve the LEED Energy & Atmosphere Green Power credit requirement, I discovered a dangerous error embedded within the LEED Online pre-formatted calculator template. In most instances, we normally correct the error and move on. But in this case, for this specific credit, it could have led to an erroneous quantity purchased in a Green Power contract with a renewable power energy ‘green-tag’ provider, which would have ultimately forfeited the credit for the project if not discovered before final submittal for certification.

Using the default percentages and manual calculations required in the LEED Reference Guide, our project needed to purchase about 705,000 kWH of green power in order to earn the credit point. However, when I entered the same parameters into the Online calculator template, the result was 25% less than my manual calculations. When brought to the USGBC's attention, they provided the following response, “We are unaware of an error in that credit template, but based on my review of your e-mail, you do seem to be correct. I would suggest that you fully fill out the template as it requests and then also submit a worksheet of your own showing the calculations you believe to be correct.”
(Christopher Davis 10/26/2007)

Key Lessons

When submitting and/or reviewing your LEED credits for review:

1. ALWAYS double-check your calculations, be wary of automated formula tools; just because it is pre-formatted does not ensure it is correct in the world of LEED tools.

2. IF you have arrived at a different calculation & result, obtain USGBC clarification where possible, and support with BACK UP documentation justifying interpretation.

3. IF the credit requires your client/owner to spend additional project budget and costs to achieve a specific LEED credit strategy or requirement, confirm the final purchase price is accurately calculated (e.g., % of electricity vs. % of energy, standard vs. BOMA area calculations, conversion factors, metric vs. English, etc.)

Although I welcome the conveniences of the LEED Online tools, I won't be ditching my manual calculator anytime soon!

CBG / NovDec 2007/ Page 2