California's investor-owned utilities are delivering programs and codes and standards enhancements (CASE) to promote ZNE, and builders are also voluntarily constructing ZNE buildings. This growth presents the need for a coordinatated, consistent definition of ZNE for buildings, including alignment with the California Energy Commision’s 2015 Integrate Energy Policy Report and ZNE definition.
TRC led a team of experts in developing new ZNE verfification methodologies for residential and non-residential buildings. The methodologies address how gross energy savings (at the building unit-level) are to be verified through the design stage and once the building is under operation.The methodologies also verify ZNE based on a range of metrics, from ZNE code to site and source energy (kBtu) for the building.
Each methodology includes the minimum amount of data required to identify a building as ZNE, the types of energy end uses included or excluded, documentation requirements for this data, and verification procedures including recommendations on verification entities.
To develop the methodologies, TRC conducted a ZNE building literature and data review, tested draft methodologies on a sample of buildings, and refined the methodologies based on results for the final report.
ZNE on a design basis is likely to be adopted into the residential building code in 2020 and 2030 for nonresidential buildings. Other entities are exploring similar standards for ZNE on a performance basis.
As this ZNE momentum grows, entities and programs responsible for verifying ZNE building status will benefit from the research and methodology recommendations TRC provides through this study. Further, California utilities and regulatory agencies receive valuable insight the implications of potential policy choices around ZNE buildings—helping them make effective and informed decisions.
Download the ACEEE paper "So you say you have built a ZNE building, prove it!"
Download our report ZNE Building Design and Performance Verification Methodologies.
For more information, visit the California Measurement Advisory Council website.
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