When Is ECC or HERS Testing Required in California?

ECC/HERS testing is required when a California project’s approved Energy Code compliance path identifies features that need field verification and diagnostic testing (FV&DT). The CEC’s ECC Program guidance uses that project-specific formulation; it does not say that every permit receives the same tests.

For help coordinating the listed measures in the Sacramento region, see Poppy Energy’s full-service ECC/HERS testing page. California ECC compliance verification is not the same product as a national RESNET HERS Index rating; the CEC separates code-compliance FV&DT from optional whole-house rating and labeling.

Common Project Triggers

The CEC’s current ECC counter sheet identifies three broad situations: newly constructed residential buildings, many HVAC alterations under the prescriptive path, and mechanical, envelope, or water-heating measures used for compliance credit under a performance path. The precise measure list still comes from the certificate for that project.

That means “trigger” is best treated as a prompt to inspect the documents, not as a universal yes/no shortcut. Project type, scope, code cycle, compliance method, equipment, distribution system, climate zone, and modeled features can change the result under the 2025 Building Energy Efficiency Standards and Reference Appendices.

The CF1R Is the Source of Project Truth

For single-family work, the CF1R Certificate of Compliance records the approved design and equipment at permit application. Energy Code Ace’s official 2025 residential forms page says CF1Rs demonstrate design-stage compliance and that projects containing ECC measures complete those documents through an ECC-Provider registry.

Look for the ECC Feature Summary on 2025-code performance documentation. The CEC says this section replaced the earlier “HERS Feature Summary” and identifies measures requiring FV&DT in its ECC Program FAQ.

Use the form names and measure IDs, not a verbal summary. The 2025 CEC forms library organizes matching CF2R installation and CF3R verification records by envelope, mechanical, water-heating, and other systems.

New Construction

The CEC states that ECC-rater FV&DT is mandatory for newly constructed single-family and qualifying multifamily residential buildings on its 2025 ECC counter sheet, with the sheet noting the multifamily scope of three habitable stories or fewer.

Do not translate that general rule into an identical test package for every home. The certificate may list different measures based on the approved compliance approach and building systems. The 2025 forms directory includes separate verification documents for such items as building leakage, QII stages, ducts, airflow, fan efficacy, refrigerant charge, and ventilation, which shows why the feature summary matters.

HVAC Changes

Many HVAC replacements and alterations require ECC/HERS documentation and testing, but not every mechanical scope has the same requirements. The CEC counter sheet describes FV&DT as prescriptively required for most HVAC alterations, while the actual certificate identifies the applicable measures.

For 2025 single-family projects, Energy Code Ace lists CF1R-ALT-02-E for prescriptive alterations to space-conditioning systems as ECC required on its residential forms page. It also lists distinct CF2R and CF3R mechanical forms, so a duct leakage test, airflow verification, fan efficacy check, or refrigerant-charge verification should never be promised solely from the phrase “HVAC changeout.”

The right workflow is to compare the proposed equipment and duct scope with the approved CF1R before installation. If you are already preparing for final, use the HVAC replacement ECC permit-closeout guide to find the missing document stage.

ADUs and Additions

An ADU can be treated as new construction, an addition, or an alteration depending on how it is created. The CEC’s 2025 ADU FAQ directs teams to classify the scope and apply the corresponding Energy Code provisions.

The 2025 forms reflect those distinctions. Energy Code Ace lists an ECC-required CF1R-ADD-01-E for certain prescriptive additions, a simple non-ECC CF1R-ADD-02-E, ECC-required alteration forms, and a simple non-ECC alteration form on its 2025 forms page. Therefore, ADU square footage alone does not answer every verification question; the approved compliance form does.

Exemptions and Uncertainty

Some scopes use non-ECC forms, and exceptions or alternate paths may apply. The CEC’s official form library expressly separates prescriptive forms for projects that do not require FV&DT from registry forms for projects that do.

Do not infer an exemption because a contractor did not include testing in a bid, because existing ducts look accessible, or because a project is small. Ask the energy consultant or building department to identify the controlling section and form. For unresolved interpretation questions, the CEC maintains an Energy Code Hotline submission form.

Scheduling Without Guesswork

Use this sequence:

1. Obtain the current approved CF1R and plan set.
2. Confirm the code cycle and whether the document says HERS or ECC.
3. List every item in the HERS/ECC Feature Summary.
4. Match each item to its CF2R installer record and CF3R rater verification using the CEC 2025 forms library.
5. Send the rater the permit address, CF1R, equipment schedule, system count, and construction stage.
6. Coordinate field access before a required feature is concealed.
7. Confirm registered documents are complete before requesting building-department final inspection; the CHEERS overview explains that building departments use the registry to confirm state energy requirements before approval.

If the feature summary is hard to interpret, continue with how to read a CF1R’s required verifications rather than ordering a generic “HERS test.”