California has the most rigorous energy code regulations in the country, and as of January 1, 2026, California’s 2025 Title 24 Energy Code is in full effect. This update has made several key changes that will impact new construction and renovation projects across California.
While the 2025 Code introduces new parameters, they also offer a roadmap to reduce long-term operational costs and enhance the market value of your assets. Let’s look at what has changed for this cycle, and how to navigate the most effective way through the new standards.
Terminology Changes and Compliance Metrics
Before diving into the details, there were a few key terminology changes for the multifamily code worth emphasizing. The Home Energy Rating System (HERS) has been renamed Energy Code Compliance (ECC). This means:
- HERS Provider is now ECC-Provider
- HERS Rater is now ECC-Rater
- HERS Rater Company is now ECC-Rater Company
- HERS Measures is now ECC Measures
Additionally, energy efficiency compliance metrics have shifted from Energy Design Rating (EDR) and Time Dependent Valuation (TDV) to Long-term Systems Cost (LSC). A building’s LSC is the projected present value of costs to California’s energy systems over a 30-year period (expressed in dollars per square foot).
This metric can be measured as Efficiency Long-term System Cost (LSCe) or Total Long-term System Cost (LSCt). LSCe represents the building’s efficiency by measuring space-conditioning, water heating, mechanical ventilation, and lighting. LSCt includes all LSCe measurements plus the photovoltaic (PV) system, battery energy storage system (BESS) and demand flexibility.
The implications for your project: These new metrics help us provide more accurate ROI projections, ensuring your building is optimized for continuous energy savings, lower operational costs, and the future energy landscape.
EV Chargers – Section 4.106.4.2
In the 2022 code, buildings with EV Ready parking spaces with charging receptacles needed 40% of total parking spaces to be equipped with low power Level 2 charging receptacles. Now, one low power Level 2 charging receptacle is required per dwelling unit assigned parking space. Buildings with unassigned parking must have one EV ready space per dwelling unit.
Buildings with EV Ready parking with Level 2 chargers previously had to equip 10% of total spaces with Level 2 chargers. The 2025 code now requires 25% of common use/unassigned spaces to have Level 2 chargers.
The implications for your project: Although EV charging standards have become more complex, by allocating electrical capacity and conduit early in the planning phase your project has infrastructure for projected growth of EV use by tenants.
Bicycle Parking – Section 4.106.4.2
There were no previous mandatory requirements for bicycle parking, unless required under CALGreen Tier 1 or Tier 2. Now there must be 1 short-term bicycle parking space for every 10,000 Sq. Ft. of conditioned floor area (CFA). There cannot be less than 2 spaces regardless of the buildings CFA and the facilities must be located within 200 feet of building entrances with anchored parking devices.
For long-term bicycle parking, there must be 1 space for every 2 dwelling units, and they must be covered or lockable enclosures with permanently anchored racks.
The implications for your project: By understanding these elevated bicycle parking standards as early as possible, you give yourself time to develop creative solutions to minimize encroachment on your rentable floor area.
Domestic Hot Water – Sections 160.4(e), 160.9(e), 160.9(f)
Mandatory Measures
Following the recent updates, hot water insulation is required for all piping (not just the recirculation loop) and ECC verification is mandatory. Infrastructure for gas water heaters must be “electric ready”. Individual systems have a new spacing requirement of 39” x 39” x 96” per heater. On the other hand, central systems need a designated outdoor space for future heat pump water pumps, or they can be inside with a pathway designed for future supply/exhaust ductwork.
Prescriptive Measures
Individual systems can no longer utilize gas or propane instantaneous water heaters in low-rise buildings. Although this does not apply to midrise buildings.
To comply with the updated central system requirements, the project must utilize a heat pump system rated at NEEA Tier 2 or higher. For systems serving nine or more dwelling units, a recirculation system is mandatory and must be equipped with a thermostatic master mixing valve.
The overall impact of these domestic hot water measures is that it is becoming more challenging to use gas water heaters. Using individual gas water heaters for low-rise will make it almost impossible to be compliant, though central gas water heaters are still feasible for compliance, but penalties may apply.
The implications for your project: With these changes, transitioning to heat pump technology significantly reduces on-site operational costs and simplifies the maintenance of your building’s mechanical systems.
Pool and Spa Heating – Section 110.4
To meet compliance, newly installed pool heating equipment must be a heat pump, solar pool heater, or a combination of both. Gas and electric resistance heaters are not allowed unless they are installed as a supplementary heater.
While gas is still allowed as a supplementary heater, this update reflects the state’s overarching movement towards decarbonization as it is no longer allowed as the main energy source in newly installed pool heating equipment.
The implications for your project: Pools must be built around renewable heating. It is key to plan infrastructure for heat pump pool heaters. These systems will significantly reduce annual energy expenses compared to traditional gas systems.
Ventilation and Compartmentalization Testing – Section 160.2(b)2AiVb1-2
In the previous code cycle, multifamily buildings had the choice to use a balanced, supply, or exhaust ventilation system. Now, exhaust-only ventilation is no longer allowed in newly constructed units. Each dwelling unit must have either balanced or supply ventilation systems to provide outside air. Compartmentalization testing (blower door test) is now required, which was previously only required for exhaust-only.
Considering the new criteria in this section, it will be important to consider the additional work and cost associated with adding more penetrations in the building’s exterior and coordinating blower door testing.
The implications for your project: Exhaust-only ventilation is out. By designing around balanced or supply ventilation systems, you create more consistent indoor air quality and improve comfort control for your tenants.
Solar Photovoltaic (PV) – Section 170.2 (f-h)
This section updated prescriptive requirements via two methods of compliance: SARA method (solar access roof area) or CFA method (conditioned floor area). Rather than a flat rate, the state now recognizes that steep-sloped roofs have higher solar potential. Thus, the multipliers based on roof type have been updated (14 W per Sq. Ft. for low sloped roofs and 18 W per Sq. Ft. for steep sloped roofs).
The implications for your project: The minimum PV system size requirements are generally increasing; however larger PV systems help offset rising utility costs.
Glazing and Cool Roofs – Section 170.2
When it comes to glazing and cool roofs, the key updates revolve around window U-value standards. A U-value measures the rate of heat transfer through a window and represents its insulation factor. In this code cycle, the U-value minimums have been updated to be higher performing than the 2022 code.
The implications for your project: More efficient window requirements can add upfront costs but designing a higher performing building envelope acts as a passive energy saver, lowering the building’s overall energy use.
Battery – Section 170.2(h)
Changes in the 2025 Code introduces updated prescriptive measures for sizing Battery Energy Storage Systems (BESS). These updates move away from the static sizing of previous years and toward BESS capacity equations that account for a building’s specific geometry and location.
The implications for your project: Batteries are more likely to be required but they offer more solutions for reducing operational costs during peak demand times.
Wall Insulation – Section 150.0 (c)
While prescriptive measures for wall insulation remain the same, the new updates have shifted the mandatory measures. Wood framed assemblies using 2×4 need to meet an insulation value of R-15 (previously R-13) and assemblies using 2×6 framing need to be R-21 (previously R-20).
The implications for your project: R-21 is the industry standard, whereas R-20 is not widely available. Like the glazing requirement, these elevated standards will lower the strain on your HVAC systems and act as a passive performer.
Want to learn more about the 2025 Title 24 Code and How to Comply
Ensuring compliance with Title 24 Energy Code can be very confusing due to the number of requirements within the code. Understanding the most recent changes presents key challenges for new developments and renovation projects.
VCA Green specializes in navigating these compliance needs via design drawings, energy modeling, compliance pathway selection, and field compliance. By bridging the gap between complex regulatory mandates and practical construction solutions, we help position each of our clients’ buildings to meet California’s evolving energy landscape.