Title 24 & HERS Testing: What to Expect When You Replace HVAC in California

Replacing an HVAC system in California legally involves a building permit and compliance with Title 24, the state's energy code — which for many change-outs includes duct leakage testing verified by a certified third-party HERS rater. A contractor who offers to "save you the permit hassle" is transferring risk to you: unpermitted work surfaces at home sale, can void insurance arguments, and skips the verification that protects your investment.

What is Title 24, in plain terms?

California's building energy-efficiency standards. For HVAC replacements it sets requirements on equipment efficiency, duct sealing, refrigerant charge verification, and airflow — the goal being that the system you paid for actually delivers its rated performance instead of leaking it into your attic.

What is a HERS test and when is one required?

A HERS (Home Energy Rating System) rater is a state-certified third party who measures things like duct leakage after qualifying change-outs. If your ducts leak beyond the allowed threshold, they get sealed and retested. It's the state independently checking the installer's work — which is precisely why good installers like it and corner-cutters route around it.

What does this mean for your project?

Practically: a slightly longer timeline than a bootleg swap, paperwork you never have to touch (we handle permit and testing coordination), and a system that demonstrably performs. It's one of the quality markers covered in the replacement guide, alongside sizing and commissioning — and one more reason installer certification is worth checking before you sign. What a proper visit looks like on the maintenance side: the tune-up checklist.

Planning a replacement? Request your free estimate — permits, Title 24 compliance, and HERS coordination included, never an upsell. Call (916) 646-2007.