California Title 24 HVAC Compliance Explained (2026 Update)

What Title 24 Actually Is

Title 24 of the California Code of Regulations is California's building energy efficiency standards. Part 6 specifically addresses energy efficiency in buildings, including HVAC. The current version is the 2022 update, which took effect January 1, 2023, with the next major update arriving 2026.

For HVAC installations in the Bay Area, Title 24 Part 6 establishes minimum efficiency requirements for equipment, mandatory verification testing for installation quality, and prescribed documentation requirements. Compliance is mandatory — every replacement AC, furnace, heat pump, or major ductwork modification must meet Title 24 requirements and document compliance.

Minimum Equipment Efficiency Requirements

The 2022 Title 24 minimum equipment efficiencies in our Bay Area climate zones (CZ3 coastal, CZ4 south coast):

• •Central air conditioner (single-stage): 15.2 SEER2 minimum
• •Central air conditioner (two-stage or variable): 16 SEER2 minimum
• •Heat pump (heating mode): 8.1 HSPF2 minimum
• •Heat pump (cooling mode): 15.2 SEER2 minimum
• •Gas furnace: 80% AFUE minimum (federal minimum)
• •Note: federal minimums (effective 2023) are 14.3 SEER2 for AC, but California requires 15.2 SEER2 — California is stricter

HERS Verification Requirements

Home Energy Rating System (HERS) verification is required for many Bay Area HVAC installations. A third-party HERS rater must test specific aspects of the installation:

Refrigerant charge verification: For all AC and heat pump installations, a HERS rater must verify the refrigerant charge is at manufacturer specification using subcool and superheat measurements. This catches under- or over-charged systems before they cause efficiency or reliability problems.

Duct leakage testing: For any installation that involves duct modification (replacement, modification, or extension), HERS testing measures total leakage. Allowable leakage: 5% of nominal airflow if ductwork is replaced; 12% if existing ductwork is retained.

Fan watt draw measurement: For new air handlers, HERS verifies the fan watt draw is at or below specification. This catches clogged filters, restrictive ductwork, and improperly-set blower speeds.

Airflow verification: For some installations, HERS verifies actual delivered airflow at the air handler matches design specs (per ACCA Manual D distribution design).

HERS verification typically adds $250-$650 to installation cost — included in our quoted pricing. The HERS rater is a separate certified professional, not the HVAC contractor, to provide independent verification.

2026 Update: What's New

The 2025 Title 24 update (effective 2026) brings several new requirements:

Stricter duct sealing for new construction (now 5% maximum leakage, down from 6%)

Mandatory ESD (Energy Savings Distribution) calculations for new ducted systems — requires Manual J, S, and D documentation

Expanded HERS verification scope to include airflow verification on more equipment

Updated minimum SEER2 thresholds (no major change in our climate zones, but stricter zones elsewhere)

Continued emphasis on heat pump pathway: incentives, prescriptive approaches, and pre-approved equipment lists favor heat pumps over gas

Permit and Inspection Process

Every HVAC installation in Bay Area cities requires a mechanical permit. The process:

Step 1 - Permit application: Contractor (us) files an electronic permit application with your jurisdiction (Palo Alto Building Department, San Mateo County, etc.). Plan check fee paid at this stage. Most jurisdictions issue permits within 5-10 business days.

Step 2 - Installation: Work proceeds after permit issuance. We post the permit on-site as required.

Step 3 - Title 24 compliance documentation: We complete CF-2R installer certification forms and provide them to the building department.

Step 4 - HERS verification: HERS rater visits within 1-2 weeks of installation completion. CF-3R verification documents filed with building department.

Step 5 - Final inspection: Building inspector visits and signs off on the permit. This typically happens 4-8 weeks after installation depending on inspector availability.

The whole process is included in our installation pricing. Skipping the permit is a bad idea — unpermitted HVAC work creates problems on resale (mandatory disclosure), voids manufacturer warranties, and creates potential liability if anything goes wrong.