Quick answer
Title 24, Part 6 is California's Building Energy Efficiency Standard. When you replace a central air conditioner, heat pump, or furnace, the work usually needs a permit from your city or county, and the installation may need third-party verification by a certified HERS rater, most commonly for duct leakage.
What HERS verification checks
A HERS rater tests the finished installation. Common checks include duct leakage, and depending on the project, refrigerant charge, airflow, and fan efficiency. If ducts leak more than allowed, they need to be sealed or replaced before the permit can close.
Why permits matter to you
Unpermitted work can cause trouble when you sell, and some rebate programs require permit documentation. A permit also means a building inspector has reviewed the installation.
Questions to ask a contractor
Will you pull the permit? Is HERS testing required for this job, and is it included? What happens if the ducts fail the leakage test? Getting these answers in writing up front avoids surprises.
