Introduction
Office Building Modernization Model:
Using the prototype models as the take-off point,
the LEED Cost Study involved a series of analyses
Two estimates were developed at the Certified,
to estimate the costs to achieve individual LEED
Silver, and Gold rating levels. At each rating level,
credits, and subsequently, overall LEED ratings at
one scenario reflected the "minimal faade
the Certified, Silver, and Gold rating levels. The
renovation" and one reflected the "full faade
evaluation process is described in the following
renovation" (as previously defined). As these
sections:
different faade scenarios reflect one of the most
significant scope variations in GSA's
Individual LEED Credit Cost Analysis
modernization projects, they were used as the basis
A detailed review of each LEED Version 2.1
for bracketing the LEED Office Building
prerequisite and credit was performed to define
modernization costs.
"typical" strategies and approaches that could be
The credit totals used in the rating scenarios were
pursued in GSA projects. Where required, LEED
as follows: 28 credits for a Certified rating, 35
calculations were performed to confirm that the
credits for a Silver rating, and 41 credits for a Gold
proposed strategies met the specific LEED
rating. These point totals are purposely 2 credits
performance criteria. For the LEED energy-
higher than the LEED minimums, as it is common
efficiency credits (EA-1), computer energy models
practice to submit additional credits to ensure that
were developed for both the Courthouse and
a rating is achieved (i.e., in case one or two credits
Office Building models to evaluate strategies and
are denied during the LEED certification process
confirm the number of LEED points that could be
with the USGBC).
earned.
For the rating scenario cost estimates, some of the
Credit costs were defined for those measures that
individual credit costs were also modified to reflect
were above and beyond the design requirements of
credit synergies. This was done by developing a
GSA's PBS-P100 and, for Courthouses, the
number of "synergistic credit" combinations for
Administrative Office of the U.S. Courts' U.S.
both the Courthouse and Office Building models.
Courts Design Guide. Separate credit costs were
The synergistic credits merge related LEED credits
developed for both the Courthouse and Office
into one overall cost estimate, which then replaces
Building models.
the individual credit estimates. For example, if a
Based on the resulting cost impacts, the individual
vegetated roof system was used to earn both credit
credits were categorized using the following key:
SS-6.1 (Stormwater Management, Rate and
Quantity) and credit SS-7.2 (Heat Islands, Roof), a
1.
GSA mandate (no cost);
new synergistic credit was defined for those two
2.
No Cost/Potential Cost Decrease;
credits in combination, and the individual credit
3.
Low Cost (< K);
costs for SS-6.1 and SS-7.2 were eliminated.
4.
Moderate Cost (K-150K); and
5.
High Cost (>0K).
For the purposes of the study, synergistic credits
were defined when: 1) a combination of LEED
LEED Rating Scenarios
credits was less expensive than the sum of the
individual credit costs (i.e., the measures to achieve
Using the individual credit costs as the basis, six
one credit also helped to achieve one or more
LEED rating scenarios were developed for both
other credits); or 2) a combination of LEED
the Courthouse and Office Building models (12
credits was more expensive than the sum of the
scenarios total). The rating scenarios were defined
individual credit costs (i.e., the measures to achieve
as follows:
one credit were made more difficult and expensive
because of the simultaneous pursuit of another
Courthouse Model:
LEED credit).
Two estimates were developed at the Certified,
Silver, and Gold rating levels. At each rating level,
LEED-related Soft Costs
one "low cost" and one "high cost" scenario was
The twelve LEED rating scenarios were also used
defined in order to bracket the LEED costs.
to define soft cost impacts. Soft cost premiums
GSA LEED COST STUDY
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