The USGBC has adopted the Core Performance Program as a prescriptive path to meet energy performance requirements of the LEED NC program. The program can be used in lieu of energy modeling to demonstrate achievement of EA credit 1 (Optimizing Energy Performance) as follows:
For projects using LEED NC version 2.2 and previous versions, the Core Performance Program is worth 2 to 5 EAc1 points, depending on project conditions and how the program is used. Any project using the Core Performance Program for LEED must meet all of the requirements in Sections One (Design Process Strategies) and Two (Core Performance Requirements) of the Core Performance Guide. No substitutions or tradeoffs are allowed in meeting these requirements. No project over 100,000 square feet may use the Core Performance Program to achieve LEED points.
The number of EAc1 points achieved by following program requirements is dependent upon project type. Office, School, Retail, and Public Assembly project types achieve 3 EAc1 points for following the program requirements. All other project types achieve 2 EAc1 points for following the program requirements. Hospital and Lab project types may not use the Core Performance Program to achieve LEED energy points. The USGBC requires all LEED 2.2 projects to achieve at least 2 EAc1 points to receive a LEED rating.
All projects using Core Performance may achieve up to 2 additional EAc1 points in LEED by implementing additional strategies from Section Three (Enhanced Performance Strategies) of the Core Performance Guide. One additional EAc1 point is achieved for every three Enhanced Performance Strategies implemented. However, some of the enhanced strategies are not eligible in LEED and do not count toward additional EAc1 points. These strategies are 3.1 Cool Roofs, 3.8 Night Venting, and 3.13 Additional Commissioning. These measures are addressed elsewhere in the LEED program.
For LEED 2009, the USGBC has modified the point structure for EAc1. All projects must exceed ASHRAE 90.1 -2007 requirements by at least 10% before any EAc1 points are awarded. The Core Performance Program is still eligible as a prescriptive path for LEED 2009. The guidelines for the program are the same as those listed above, except that in every case the first two 'points' are not counted in EAc1 but instead go toward meeting the prerequisite requirements of this credit.
For example, a lodging project which would have achieved two points in LEED NC 2.2, would achieve zero EAc1 points in LEED 2009, but would meet the prerequisite requirements of EAp2 and therefore not be required to conduct energy modeling. This project could still achieve up to 2 EAc1 points by implementing Core Performance enhanced strategies as described above.
Office, School, Retail, and Public Assembly projects which implemented Sections One and Two of the Core Performance Guide, would achieve the prerequisite as well as one EAc1 point. These projects would also be eligible to achieve up to two additional EAc1 points by implementing enhanced strategies, as described above.
LEED C1 projects may use a subset of Core Performance (sections 1.4,2.9, and 3.10) to achieve EAc1 points, as described in the LEED Reference Guide.
The USGBC has developed submittal requirements for the Core Performance Program as part of the LEED on-line submittal process. The USGBC may modify the way LEED uses Core Performance, so project teams should check with the USGBC for any modifications to the requirements described here.
2.6 FENESTRATION PERFORMANCE
Meet specific window performance Criteria for u-value and solar heat gain coefficient, based on NFRC ratings. Performance requirements are based on entire window assembly, not glazing alone.
Promote the installation of high-performance glazing systems, and the use of a consistent performance rating standard for these products.
Window systems, which are part of the building envelope, where window and glazed door area is not greater than 40% of the gross area of above-grade walls, shall meet the Criteria shown in Table 2.6.1.
Each vertical fenestration system must meet the U-Factor, the SHGC for the corresponding projection factor, and the VLT specification. Skylight systems, which are a part of the roof assembly where the skylight area is not greater than 5% of the gross roof area, shall meet the Criteria shown in Table 2.6.2. Each horizontal fenestration system must meet the U-factor and the SHGC. Note: buildings where window and glazed door area is greater than 40% of the gross area of above-grade walls or skylight area is greater than 5% of the gross roof area must conduct energy modeling to demonstrate equivalent performance.
All fenestration (windows, skylights and doors) must be rated according to the requirements of the National Fenestration Rating Council (NFRC) with respect to the performance of the fenestration in the categories of U-value, Solar Heat Gain, Coefficient and Visible Light Transmittance, and air leakage rate. NFRC ratings account for the performance of the frame/mullion/spacer/glazing system as a whole.