For example, in Appendix G credit is available for strategies not credited in ECB such as optimized window area and orientation, selection of more efficient HVAC and service water heating equipment type, right sizing HVAC equipment, efficient use of thermal mass, etc. Appendix G uses a more independent baseline where many of the characteristics of the baseline design are based on standard practice, meaning credit is available not only for exceeding prescriptive requirements in the code, but also for exceeding standard practice that is not regulated by the code.This approach is referred to as a dependent baseline. A building is deemed in compliance with ECB when the annual energy cost of the proposed design is no greater than the annual energy cost of the baseline building design.The baseline is essentially a clone of the proposed design with most of the building components adjusted to “just meet” current prescriptive requirements.The main differences between the ECB and PRM approaches in Standard 90.1 are the characteristics of the baseline building design. This is demonstrated using computer simulation to compare a proposed building design to a reference building design commonly referred to as a baseline. These methods provide more flexibility by allowing a designer to "trade off" compliance by not meeting some prescriptive requirements if the impact can be offset by exceeding other prescriptive requirements. The two performance-based approaches in Standard 90.1 are the Energy Cost Budget (ECB) method found in Section 11 and the Performance Rating Method (PRM), commonly referred to by its location in the Standard, Appendix G.
The prescriptive path establishes criteria for energy related characteristics of individual building components such as minimum R-values of insulation, maximum U-factors and solar heat gain coefficients of fenestration, maximum lighting power allowance, occupancy sensor requirements for lighting control, and economizer requirements for HVAC systems.(e.g. check the cold room ventilation rate listed in ASHRAE 62.Commercial building energy codes such as ASHRAE Standard 90.1 typically include two types of approaches for demonstrating compliance prescriptive and performance paths. But I suspect project teams will be able to use more current standards on LEED v3 and v4 projects on a case-by-case basis. USGBC may not create a credit substitution list like they did for v4 into v3. LEED NC v4.1 is in BETA, and is expected to be for the entirety of 2019. LEED NC v4.1 EAc2 requirements are outlined at: LEED NC v4.1 EAp1 requirements are outlined at: Read only version of ASHRAE 90.1-2016 is available at: manufacturing) will be able to use the percent threshold that has been reserved for Healthcare, CS, and Major Renovations.
After discussions with top folks within USGBC/GBCI it also sounds like projects with 50%+ unregulated energy use (e.g.
Up to 9 points for reducing energy cost and up to 9 points for reducing GHG. LEED v4.1 splits the energy modeling points into two point thresholds - Performance Cost Index (PCI) & greenhouse gas (GHG) emissions. We have a call with GBCI today, since it seems like the language contradicts each other. Appendix G allows the baseline efficiency to be taken from Appendix Table G3.5.1, which is much less stringent than Table 6.8.1. The mandatory provisions point to minimum efficiency tables (e.g. The interior lighting power allowance can be determined using either Tables G3.7 or G3.8 and the methodology described in Sections 9.5.1 and 9.6.1. Both LEED v4.1 EAp2 & 90.1-2016 Appendix G requires conformance with mandatory provisions listed in Sections 5.4, 6.4, 7.4, 8.4, 9.4, and 10.4.