Starting in 2013, the US Department of Energy (DOE) has worked to advance high-performance, high-quality homes through its DOE Zero Energy Ready Home (ZERH) certification program and by recognizing and establishing guidelines for highly energy-efficient residential buildings. The ZERH has accelerated the adoption of cost-effective building technologies.
ZERH Multifamily Version 2 increases energy efficiency and performance levels, adds electric readiness, and makes the compliance pathways and certification process more consistent with the ENERGY STAR Multifamily New Construction program. Before this new version, multifamily buildings up to five stories in height were eligible for certification under Version 1. Under the recently released Version 1, Revision 9, both low-rise and high-rise multifamily buildings became eligible for ZERH certification; version 2 maintains this expanded eligibility.
Version 2 will be required for projects with permit dates on or after 1/1/25. (Projects with permit dates from 1/1/24 to 12/31/24 must certify under ZERH Multifamily Version 2 or ZERH Version 1, Revision 9.)
According to the DOE, the Version 2 program requirements promote energy efficiency by:
- Requiring certification under ENERGY STAR Multifamily New Construction Version 1.2;
- Requiring certification under Indoor airPLUS V1 (for permit dates on or before 12/31/25) and Indoor airPLUS V2 Certified or Gold tier (for permit dates on/after 1/1/26);
- Increasing the stringency of envelope insulation and window requirements;
- Including PV-ready and EV-ready checklists tailored for multifamily buildings;
- Incorporating electric-ready provisions to accommodate future heat pump installations for space and water heating;
- Providing three pathways for certification: Energy Rating Index (ERI), ASHRAE 90.1, and Prescriptive; and
- Increasing the minimum required efficiency threshold, bringing ERI scores to qualify for ZERH to the mid-40s. The ASHRAE and Prescriptive pathways are designed to achieve a similar level of energy efficiency.
The DOE has released the following program documents related to Version 2:
- DOE Zero Energy Ready Home Multifamily National Program Requirements Version 2
- DOE Zero Energy Ready Home Multifamily National Rater Checklist Version 2
- DOE Zero Energy Ready Home Multifamily PV-Ready Checklist Version 2
- DOE Zero Energy Ready Home Multifamily EV-Ready Checklist Version 2
- DOE Zero Energy Ready Home Multifamily ERI Target Procedure Version 2
- Summary of Major Changes from ZERH Version 1 to ZERH Multifamily Version 2