Introduction
Many homeowners and contractors are surprised to learn that replacing an HVAC system in California — even a like-for-like equipment swap — can trigger Title 24 compliance requirements including HERS verification. Understanding when a HERS Rater is required for an HVAC replacement, and what they need to test, can help you plan the project and avoid unexpected delays or costs.
Does Every HVAC Replacement Require Title 24 Compliance?
Not every HVAC replacement triggers Title 24 HERS requirements, but many do. The key factors are the scope of work and the climate zone.
A complete system replacement — replacing both the indoor air handler and the outdoor condensing unit — almost always requires a Title 24 compliance calculation and, in many cases, HERS verification. Replacing only the outdoor condensing unit while retaining the existing air handler and duct system may or may not require Title 24 compliance depending on the equipment efficiency and climate zone.
A like-for-like equipment replacement of the same type and capacity sometimes qualifies for simplified compliance, but the equipment must meet the minimum efficiency requirements of the 2022 Title 24 standards (the current standards). Older, lower-efficiency units being replaced may require upgrading to a more efficient model to comply.
Common HERS Verification Requirements for HVAC Replacements
When HERS verification is triggered by an HVAC replacement, the most common required measures include duct leakage testing (if the existing duct system is being retained with a new air handler, duct leakage testing is frequently required in many California climate zones), refrigerant charge verification (new refrigerant charge must be verified to confirm the system is properly charged — an improperly charged system runs inefficiently and wears out faster), airflow measurement (confirming adequate airflow across the coil), and fan efficacy verification (confirming the air handler fan operates within the efficiency requirements).
The specific measures required on your project depend on the equipment being replaced, the climate zone, and what the energy consultant specifies on the compliance documentation.
Climate Zone Matters
California's 58 counties span 16 climate zones with different weather profiles and different HVAC requirements. The HERS verification requirements for HVAC replacements vary by climate zone. Inland areas with high cooling loads (climate zones 9, 10, 11, 12, 13, 14) typically have more stringent HVAC verification requirements than coastal areas with mild climates.
Your energy consultant will determine the applicable requirements for your project's climate zone.
The Role of the Title 24 Energy Consultant for HVAC Replacements
For an HVAC replacement that requires Title 24 compliance, an energy consultant must prepare a compliance calculation and generate a CF1R. The CF1R specifies the required equipment efficiency ratings, the HERS verification measures, and any other compliance requirements.
The HVAC contractor then completes the CF2R — a self-certification that the equipment was installed as specified. The HERS Rater visits the site, performs the required tests, and submits data to the HERS registry to generate the CF3R. All three documents may be required for permit sign-off depending on the scope of work and local building department requirements.
Practical Advice for Homeowners and Contractors
Get a permit. Many HVAC replacements in California require a permit from the local building department. Unpermitted HVAC work creates liability and can complicate future home sales. Permitted HVAC work ensures the compliance and verification process runs properly.
Engage the energy consultant early. The Title 24 calculation must be done before installation, not after. Call an energy consultant at the same time you're getting HVAC contractor bids.
Ask the HVAC contractor about HERS coordination. Experienced contractors who regularly work on California projects understand HERS requirements and can help coordinate the HERS Rater site visit at the right point in the project. Refrigerant charge verification must be done after the system is fully installed and running. Duct leakage testing should happen before any access panels are sealed.
Choose HERS-verified equipment where possible. Some HVAC equipment is available in configurations pre-approved for HERS verification, which can streamline the field verification process.
Conclusion
HVAC replacements in California frequently trigger Title 24 compliance requirements, including HERS verification for duct leakage, refrigerant charge, and airflow. The specific requirements depend on your climate zone, the scope of work, and the equipment involved. Getting a permit, engaging an energy consultant before installation, and coordinating your HERS Rater at the right point in the project are the keys to a smooth process.