California Title 24 HVAC Replacement Requirements
Replacing a central air conditioner, furnace, or heat pump involves equipment selection, permit requirements, and energy compliance. The details depend on the building, the work being performed, and the code edition that applies to the project.
This guide focuses on HVAC replacements in existing single-family homes, with permitting resources for Los Angeles and Ventura counties. Multifamily buildings, commercial properties, and new construction have different provisions.
Before approving a replacement, ask which department will issue the permit, which tests and forms apply, and who will arrange and pay for each step.
Last reviewed: November 2, 2026
Which Title 24 Code Applies?
Title 24 is California's Building Standards Code. Part 6 contains the Building Energy Efficiency Standards, commonly called the Energy Code. Mechanical installation and permit rules also involve other code provisions and local administration.
The 2025 Energy Code applies to projects with permit applications submitted on or after January 1, 2026. An earlier project may fall under a previous edition. Use the project's applicable code cycle when checking requirements and forms.
Does a Like-for-Like HVAC Replacement Need a Permit?
Plan on a mechanical permit when replacing permanently installed central heating or cooling equipment. Replacing a unit with a similar model does not, by itself, establish a permit exemption.
Confirm the requirements with the building department for the property. Routine servicing, individual repairs, portable appliances, and equipment replacement can be treated differently. Additional electrical or other work may affect the permit scope.
A submitted application is not the same as an issued permit. Ask for the permit number and confirm its status before work that requires authorization begins.
Find the Correct Building Department
Use the street address or parcel information to identify jurisdiction. A ZIP code or mailing city alone may not identify the responsible office.
Properties Within the City of Los Angeles
The Los Angeles Department of Building and Safety, or LADBS, is a City of Los Angeles agency. It is distinct from Los Angeles County Public Works.
Unincorporated LA County & Contract Cities
LA County Public Works provides building services for unincorporated communities and certain cities. Its permit page links to an address-based service locator that identifies the appropriate office.
Calabasas & Other Incorporated Cities
Calabasas has its own Building and Safety Division. Other incorporated cities may administer permits themselves or through contracted services. Confirm the arrangement for the actual property.
Ventura County Properties
Ventura County Building and Safety issues permits for unincorporated areas. For a property within an incorporated city, check the city's building department or its designated service provider.
What Is ECC Verification, and What Happened to HERS?
Under the 2025 Energy Code, the Energy Code Compliance program covers the field-verification and diagnostic-testing functions previously handled through the HERS code-compliance program. Older code-cycle documents can still use HERS terminology.
ECC raters are certified through CEC-approved providers. They verify specified energy measures under the program's certification and conflict-of-interest rules. Their role is separate from the installer's work and the building department's inspection.
The required measures depend on the project. Verification can involve duct leakage, airflow, refrigerant charge, or other specified features; every project does not require every available test. Confirm the required measures and who will coordinate the rater before installation.
Which Duct-Leakage Requirement Applies?
Equipment replacement and duct replacement are different scopes. Under the 2025 single-family alteration provisions, replacing specified heating or cooling equipment can trigger sealing and verification of the connected ducts, subject to the applicable exceptions.
Existing Ductwork Retained With an Equipment Change
For covered alterations retaining existing ducts, the standard compliance routes include measured total leakage of no more than 10% of system air-handler airflow, or leakage to outside of no more than 7%.
Where those criteria cannot be met, the applicable provision allows an alternative involving sealing accessible leaks and ECC verification through visual inspection and a smoke test. This is a defined compliance route that must meet its conditions.
An Entirely New or Complete Replacement Duct System
A duct system meeting the code's definition of entirely new or complete replacement has a 5% leakage criterion under Section 150.2(b)1Dii(a). Replacing the AC or furnace alone does not make retained ducts a new duct system.
Exceptions & Special Conditions
Documented previous sealing, short duct systems, and garage installations can affect which provisions apply. Ask the contractor and rater to identify the specific requirement or exception for your project.
A genuinely ductless installation has no distribution ducts to leakage-test, but other energy requirements or verification may still apply.
The percentages above compare measured duct leakage with system airflow. They do not state the percentage of your utility bill being lost.
What If Existing Ducts Need Work?
A home's age alone does not establish whether its ducts will pass a test or need replacement. Inspection and applicable testing help identify leakage, damaged sections, connection issues, and the work required.
Ask the proposal to explain how additional duct work will be assessed, approved, and priced if it becomes necessary. Sealing materials and workmanship matter, but applying more sealant does not guarantee a passing result.
Understand CF1R, CF2R & CF3R Documents
Single-family energy compliance documents serve different purposes:
| Document | What it records |
|---|---|
| CF1R — Certificate of Compliance | How the proposed project meets the applicable energy requirements. |
| CF2R — Certificate of Installation | The responsible installer's declarations about the installed measures. |
| CF3R — Certificate of Verification | Required field-verification results recorded by the ECC rater. |
The applicable forms depend on the scope and code cycle. Projects requiring ECC verification use registered compliance documents through an approved provider's registry. Some projects without verification requirements use different forms.
Ask which documents are due during permitting and at final inspection. Certain HVAC changeouts have a special submission-timing provision, so a registered CF1R is not universally required before permit issuance. Confirm the procedure with the enforcement agency.
How Installation, Verification & Final Approval Fit Together
The contractor completes the agreed installation and applicable installer checks and documentation. Any required ECC verification then documents the specified energy measures. The building department handles the required inspections and final approval for the permit.
Some checks or inspections may occur earlier in the work. Confirm the required sequence and access arrangements, especially before work is concealed. If corrections are required, they must be resolved through the appropriate process.
A passing ECC test does not automatically close a mechanical permit. At completion, verify the final inspection result and permit status with the issuing department.
Questions to Ask Before Approving the Proposal
Use these questions to compare the scope of competing estimates:
- 1What equipment and ductwork are being replaced or retained?
- 2Which building department and code edition apply?
- 3Who obtains the permit, and are its fees included?
- 4Which energy forms and verification measures are required?
- 5Who arranges testing, pays the rater, and handles any retesting?
- 6How will additional duct repairs or other changes be approved and priced?
- 7Who schedules final inspection and provides the completion records?
The estimate should make these responsibilities clear. A price described as “installation included” may not explain every permit, testing, or correction cost.
Records to Keep After the Replacement
Keep the issued permit and final approval record, applicable completed energy forms, equipment model information, the invoice, and any warranty documents supplied with the project. These records help you identify what was installed and what was approved when arranging future service or reviewing property records.
If a required document or final approval is missing, contact the contractor and issuing building department to determine the outstanding steps. A service invoice alone does not show the permit's final status.
Discuss Your HVAC Replacement With Wind Flow AC
Wind Flow AC provides HVAC replacement and installation services across Los Angeles County / Valley Area, the 101 Corridor, and Ventura County. Our office is in Calabasas.
Share your property address, existing equipment, and proposed changes. We can discuss the installation and the permit, documentation, and testing responsibilities to include in the proposed scope.
Calabasas, CA 91302
Saturday: Closed
Sunday: 8:00 AM–7:00 PM