California HERS to ECC in 2026: What Changed

California’s familiar “HERS testing” language changed for 2025 Energy Code projects, but the work did not disappear. The state now calls the compliance program Energy Code Compliance (ECC) and the field professional an ECC-Rater. Poppy Energy’s full-service ECC/HERS testing page keeps both terms visible because permit teams may encounter either one depending on a project’s code cycle.

This guide explains the state transition. It is not about a national RESNET HERS Index rating: California’s CEC distinguishes mandatory field verification and diagnostic testing from optional whole-house rating and labeling.

Effective Date: When California ECC Began

The ECC Program became effective with the 2025 Energy Code on January 1, 2026, and permit applications submitted on or after that date must use the 2025 code and approved 2025 compliance software, according to the California Energy Commission’s current compliance-software guidance.

That date is a code-cycle boundary, not a rule that every open project must be converted. The CEC says 2016, 2019, and 2022-code projects remain mostly unaffected; their documents continue to use the terminology and procedures associated with the applicable earlier code.

Terminology Mapping

The CEC’s ECC Program FAQ provides the clearest mapping for 2025-code work:

Earlier project language	2025 Energy Code language	Practical meaning
HERS Program compliance verification	ECC Program compliance verification	California field verification and diagnostic testing used to demonstrate Energy Code compliance
HERS Provider	ECC-Provider	CEC-approved administrator that certifies and oversees raters and operates an approved registry
HERS Rater	ECC-Rater	Certified field professional who verifies measures within an approved scope
HERS Feature Summary	ECC Feature Summary	Certificate of Compliance section identifying project features that require field verification

Many contractors and homeowners will continue saying “HERS test.” That shorthand can be useful, but the project documents decide the actual program, code cycle, forms, and verification scope.

What Changed

For 2025-code compliance tools and documents, references to HERS were replaced with ECC or field verification and diagnostic testing (FV&DT) depending on context. Program administration also moved: the CEC explains that the former compliance-verification portion of the HERS regulations was relocated into the Energy Code, while optional whole-house rating remained outside the ECC compliance program in its ECC transition explanation.

The 2025 forms reflect the new naming. The official 2025 single-family forms directory lists Certificates of Compliance (CF1R), Certificates of Installation (CF2R), and Certificates of Verification (CF3R), and identifies forms used when ECC measures apply.

There are also code-cycle-specific technical revisions, so a team should not simply relabel an old checklist. The CEC identifies changes such as removal of alteration-project group sampling and revisions to refrigerant-charge verification methods on its ECC Program page.

What Did Not Change

Field verification still connects design, installation, rater verification, registry documentation, and building-department enforcement. The CEC’s 2025 forms page describes CF1R documents as design-phase compliance records, CF2R documents as installation records, and CF3R documents as verification records.

The approved Certificate of Compliance remains the project-specific source for which features require FV&DT. The CEC’s 2026 ECC counter sheet tells enforcement staff and project teams that required FV&DT is specified on that certificate.

Nor did ECC turn California compliance work into a national RESNET HERS Index. The CEC explains that “HERS I” compliance testing moved to ECC while “HERS II” whole-house ratings did not. A project seeking a national index needs a separately defined rating scope.

What About Old-Code Projects?

First confirm the permit-application date and the code edition shown on the approved documents. The CEC Energy Code Hotline page states that applications on or after January 1, 2026 use the 2025 Energy Code, while applications on or after January 1, 2023 used the 2022 code.

Then keep the project internally consistent. A 2022-code job can still show “HERS” on its forms even though the active professional may now be recognized as an ECC-Rater. The CEC says active certifications remain intact by code cycle and that a rater must complete 2025 certification to perform 2025-code FV&DT in its rater transition guidance.

If the permit was revised, expired, or reissued, ask the authority having jurisdiction and energy consultant which code edition governs rather than inferring the answer from the construction date. The CEC offers its Energy Code inquiry form for project-specific code questions.

Homeowner and Contractor Action List

1. Find the approved compliance documents. Use the actual CF1R or equivalent certificate, not a proposal or equipment invoice, to identify the project scope and listed verification features; the Energy Code Ace 2025 forms directory explains the CF1R’s permit-stage purpose.
2. Confirm the code cycle. Match the permit date, compliance software, forms, and rater certification to the applicable edition using the CEC’s 2025 software page.
3. Use the right vocabulary in scheduling. Send the CF1R and say whether it is a 2022 HERS project or 2025 ECC project so the provider and rater can place it in the appropriate workflow.
4. Coordinate access with the rater early. Poppy scheduling recommendation: ask the rater when each listed measure must be accessible before the related work is covered. The controlling procedures vary: 2025 Reference Residential Appendix RA3.1 distinguishes final and rough-in duct-leakage configurations, while RA3.5 contains the QII installation and inspection protocols.
5. Do not assume “no HERS” means “no ECC.” Read the 2025 certificate’s ECC Feature Summary and use the guide to when ECC/HERS testing is required to organize the next questions.

The practical takeaway is simple: preserve the code cycle, follow the approved certificate, and coordinate the installer, ECC-Provider registry, ECC-Rater, and building department around the same documents.