California is on the move again with its building standards. Starting January 1, 2026, permits will fall under the 2025 California Energy Code (Part 6), 2025 CALGreen (Part 11), and the 2025 California Mechanical Code (CMC).
If you’re an HVAC installer, here’s a clear rundown of what’s changing compared to today’s 2022/2024 cycle—and what it means when you’re out in the field.
The Code Cycles at a Glance
Now (2022 cycle with July 2024 updates):
- 2022 Energy Code (Part 6)
- 2022 CALGreen (Part 11)
- 2022 California Mechanical Code (with 2024 supplements)
Next (effective Jan 1, 2026):
- 2025 Energy Code (Part 6)
- 2025 CALGreen (Part 11)
- 2025 CMC
1. Residential Space Conditioning
The big shift: Heat pumps are the new prescriptive default.
Starting in 2026, every climate zone defaults to heat pumps for space heating under the prescriptive path. Gas furnaces aren’t banned, but you’ll need a performance model if your client insists on one.
There are also stricter controls and setup requirements:
- Defrost delay must be set to ≥90 minutes (installer certifies this).
- Supplemental electric heat lockout above 35°F, capped at 2.7 kW per ton.
- Thermostats must:
- Show outdoor temperature.
- Indicate when supplemental heat is running.
- Lock out supplemental heat above 35°F to maximize energy savings by relying on the more efficient heat pump operation whenever possible.
- Fan/airflow rules expand for multi-speed and variable systems.
- Mechanical ventilation requirements tighten—IAQ filter access, ERV/HRV core access, and outdoor air intake placement/clearances all matter.
- Refrigerant charge verification expands (HPs in all zones; ACs in specific zones).
What’s different from today:
The 2022/2024 code strongly pushed heat pumps, but 2026 locks them in as the prescriptive baseline with new lockouts, displays, and airflow rules.
2. Nonresidential HVAC
New in 2026:
- Mechanical heat recovery is now prescriptive (new 140.4(s)).
- Cooling tower efficiency raised (axial fan open-circuit towers).
- Small packaged RTUs/HPs (<65k Btu/h) get specific alteration requirements (Table 141.0-E-1).
What’s different from today:
2022 had efficiency rules but didn’t mandate heat recovery or these tower efficiency levels, nor did it call out small packaged RTUs in alteration work.
3. Refrigerants & the Mechanical Code (A2L Transition)
Big picture: No new cliff in 2026.
California already jumped early on A2L refrigerants (low-GWP) in July 2024. The 2025 CMC just normalizes this to model code language instead of California-only amendments.
Practical reality:
- You’re already installing A2L-ready equipment.
- You’re already handling detector placement, shaft ventilation, UL 60335-2-40 listings, and tech safety training.
- CARB’s HFC rules continue to drive the market toward low-GWP refrigerants (≤700–750 GWP, depending on product class).
So, in 2026, nothing “new” here—just continuation.
4. CALGreen Provisions (Mainly Nonresidential)
Testing, adjusting, and balancing (TAB) requirements remain mandatory for new systems and smaller nonresidential buildings. Expect continued emphasis on procedures and documentation.
There are no big new requirements, but budget time for paperwork and commissioning.
Practical Checklist for Installers
Residential (single-family/low-rise MF)
- Plan on heat pumps for prescriptive compliance.
- Update startup sheets:
- Defrost ≥90 minutes
- Supplemental heat lockout at 35°F
- 2.7 kW/ton cap
- Thermostat outdoor temp + heat indication/lockout
- Refrigerant charge verification submittals
- Pay attention to ventilation/IAQ accessibility when installing HRVs/ERVs.
Nonresidential
- For retrofits, check if heat recovery, cooling tower efficiency, or RTU/HP rules apply.
- Schedule extra time for commissioning/TAB deliverables.
Refrigerants
- Keep following your 2024 A2L best practices: detectors, ventilation, UL-listed components, and technician training.
Bottom Line
For HVAC, 2026 is about formalizing what’s already been trending:
- Residential: Heat pumps as the prescriptive default, with tighter setup/controls and verification.
- Nonresidential: New heat-recovery, cooling-tower efficiency, and small-RTU requirements.
- Refrigerants: Continue A2L practices you started in 2024—no new cliff.
If you prep now with updated startup sheets, commissioning processes, and crew training, the 2026 cycle won’t catch you by surprise.