scope:

FOREWORD

Currently, Section 11 and Appendix G allow unlimited trade-offs between building envelope and other building systems. Studies have concluded that weaker building envelopes can permanently limit building energy performance, even as lighting and HVAC components are upgraded over time, because retrofitting the envelope is less likely and more expensive. This issue has been raised by states and jurisdictions around the country. Language to limit the envelope trade-offs on projects following performance path of compliance (aka the envelope backstop) will be included in the New York City and Washington State energy codes among others.

Addendum cr builds on this prior work, striving to preserve design flexibility and minimize documentation effort while improving the long-term building performance. Projects can comply with the proposed envelope backstop by either meeting the prescriptive envelope requirements in Section 5.5 or using Section 5.6 "Building Envelope Trade-Off Option" to demonstrate that the energy cost penalty from the proposed below-code envelope does not exceed the set margins. The backstop margins (15% for residential building area types and 7% for nonresidential building area types) were tested on projects in Climate Zones 2A, 4A, and 6A building types, including multifamily residential, hotel, office, school/university, and standalone retail, light weight, and mass wall construction with high and low window area.

Note: In this addendum, changes to the current standard are indicated in the text by underlining (for additions) and (for deletions) unless the instructions specifically mention some other means of indicating the changes.