ECC stands for Energy Code Compliance. It is California's official program for verifying that energy efficiency measures in homes and buildings are installed correctly and perform as required by the California Energy Code — Title 24, Part 6.

The California Energy Commission (CEC) created the ECC Program by moving field verification and diagnostic testing provisions directly into the Building Energy Efficiency Standards (Title 24, Parts 1 and 6), replacing the older HERS Program regulations. The result is a program built around one clear goal: making sure energy efficiency measures actually work.

Title 24 is the California Building Standards Code. Part 6 is the Energy Code — the rules governing minimum energy efficiency requirements for residential and nonresidential buildings, covering HVAC, insulation, windows, water heating, ventilation, and more. It is updated every three years. The 2025 Energy Code, effective January 1, 2026, is the first code cycle to fully incorporate the ECC Program.

What Happened to HERS?

The HERS (Home Energy Rating System) program was California's previous energy verification system. HERS Raters visited job sites, ran diagnostic tests, and documented whether installed systems met code. The ECC Program continues that work — with updated regulations, a direct connection to the Energy Code, and a new name. HERS Raters are now called ECC Raters.

What is Field Verification and Diagnostic Testing?

When a project's Certificate of Compliance requires certain energy measures to be tested, a certified ECC Rater visits the job site to physically inspect and test those installations. If a measure fails, the contractor must correct it and retest until it passes. The rater then submits a Certificate of Verification to the data registry — the official record that code compliance has been met.

This process protects homeowners from defective installations, helps contractors catch problems early, and gives building departments the documentation needed to close a permit.

What Gets Tested?

The 2025 Reference Appendices identify every measure requiring ECC verification. Common examples include:

HVAC and Duct Systems — Duct sealing and leakage, duct location and insulation R-value, return duct design, air filter device design, and low-leakage air-handling units.

Air Conditioning and Heat Pumps — Refrigerant charge, system airflow, fan efficacy, EER2 and SEER2 ratings, heat pump capacity, and variable capacity heat pump systems.

Ventilation — Whole-building mechanical ventilation airflow (mandatory for new construction), kitchen local exhaust, and heat/energy recovery ventilation performance.

Building Envelope — Air leakage and compartmentalization, Quality Insulation Installation (QII — required for most new construction), and spray polyurethane foam insulation.

Water Heating — Pipe insulation, compact hot water distribution, demand recirculation systems, and drain water heat recovery units.

Who is an ECC Rater?

An ECC Rater is a certified, independent third-party professional trained to perform field verification and diagnostic testing. By law, ECC Raters must be independent from the builder and the installing contractor — which is what makes their verification credible.

The rater reviews compliance documents, performs all required tests, records results in the data registry, and signs the Certificate of Verification. A copy must be left in the home for the building owner.

Who is CHEERS?

CHEERS (California Home Energy Efficiency Rating Services) is currently the only CEC-approved ECC Provider in California. ECC Providers are responsible for training and certifying ECC Raters, maintaining quality control over rater work, and operating the residential data registry where all compliance documentation is submitted and stored.

After an ECC inspection, CHEERS may contact the homeowner for a quality assurance follow-up visit — this is a required part of the program and ensures accuracy across all rater work statewide.

When is ECC Testing Required?

ECC testing is required when a permitted project includes measures that the Energy Code specifies must be field verified or diagnostically tested. The most common situations are:

New home construction — Most new single-family homes require ECC verification of multiple systems.

HVAC replacements and upgrades — One of the most common triggers for ECC testing in existing homes.

ADUs — Treated as new construction for Energy Code purposes; full ECC verification typically required.

Additions and remodels — Depending on scope, alterations can trigger testing requirements.

Your contractor should know whether your project requires ECC testing before work begins. For urgent replacements like an emergency HVAC changeout, documentation may be registered after the work is completed but must be on file before the permit closes.

For Homeowners

You have the right to hire your own ECC Rater, independent of your contractor. Ask your contractor upfront whether ECC testing is required. Request copies of your compliance documents when the work is done — they are required to be left in your home. If CHEERS contacts you for a quality assurance visit after your inspection, that is normal and required.

For Contractors and Builders

The 2025 process will feel familiar if you've worked under HERS. The key differences: all "HERS" terminology on 2025 compliance documents becomes "ECC" or "FV&DT," group sampling for alterations has been removed, refrigerant charge verification methods have been revised, and fault indicator displays (FID) alone may no longer be used to demonstrate RCV compliance. Rater certifications and provider agreements must be updated for the 2025 code cycle through CHEERS.

Schedule Your ECC Inspection

California Energy Code Compliance™ serves homeowners, contractors, and builders throughout San Luis Obispo, Santa Barbara, Ventura, and Los Angeles Counties.

Call us at 805.813.1204 or use our contact form to get started.