Short answer: Title 24 requirements are the energy-efficiency rules in Part 6 of California's Building Standards Code. They set minimum standards for insulation, windows, heating and cooling, water heating, ventilation, lighting and, for most new homes, solar PV. Which requirements apply depends on your project type, scope of work and climate zone, and a Title 24 report shows how your design meets them.
What Are Title 24 Requirements?
California Title 24 requirements are the minimum energy standards a building must meet to receive a permit. They are written by the California Energy Commission (CEC) and updated about every three years; the current Title 24 code cycle is the 2025 Standards, which apply to permit applications submitted on or after January 1, 2026.
The requirements fall into three groups:
- Mandatory measures apply to every project in scope, whichever compliance method is used.
- Prescriptive requirements list a minimum for each component, varying by climate zone.
- Performance requirements set an overall energy budget. The design is modeled and compared with a code-built "standard design," which allows trade-offs between features. We explain this in Title 24 calculations.
Title 24 Requirements by Building System
Building envelope and insulation
Walls, roofs, ceilings and floors that separate conditioned space from the outdoors must meet insulation and construction requirements. Air sealing and, in many cases, field-verified quality insulation installation also apply. Hotter and colder climate zones generally call for stronger envelope performance.
Windows and glazed doors
Windows are rated for how much heat they let through (U-factor) and how much solar heat they admit (SHGC). The code sets limits on both, and on how much glazing a building can have before trade-offs are needed. Replacement windows usually need to meet current ratings too — see window replacement rules.
Heating, cooling and ducts
Equipment must meet minimum federal and state efficiency ratings, and ducts must be sealed and insulated. Many systems need HERS field verification, such as duct leakage and refrigerant charge testing. Recent code cycles strongly favor heat pumps.
Water heating
Water heaters must meet efficiency requirements, and the code's baseline increasingly assumes heat pump water heating. Gas water heaters may still be possible in some cases, often with trade-offs elsewhere in the design.
Ventilation and indoor air quality
Homes need whole-house mechanical ventilation, kitchen and bathroom exhaust, and, in many cases, verified fan airflow. Tighter building envelopes make these measures more important.
Lighting
Residential lighting must be high-efficacy, with controls such as vacancy sensors or dimmers in certain rooms. Nonresidential lighting has its own, more detailed requirements.
Solar PV and battery storage
Solar PV has been required on most newly constructed single-family homes since the 2019 Standards. Some ADUs and additions have exceptions, and battery storage requirements or credits depend on building type and code cycle. The Title 24 report determines whether and how they apply.
Title 24 Requirements by Project Type
The same building systems are covered on every project, but the scope of work controls how much of the code applies.
- New construction: the whole building must comply, usually through the performance method, including solar PV where required.
- ADUs: new detached ADUs are treated much like small new homes; attached ADUs and garage conversions are often handled as additions or alterations. See ADU energy compliance.
- Additions: the new space must comply on its own, or the addition and existing home can be modeled together. See additions and Title 24.
- Alterations — HVAC: replacing a furnace, air conditioner or heat pump can bring in duct sealing and HERS testing requirements. See HVAC replacement.
- Alterations — windows: replacement windows generally need to meet current efficiency ratings, and larger projects may need a report.
Not every project needs a report. See when Title 24 is required for common triggers and exemptions.
Title 24 Requirements by Climate Zone
California has 16 energy climate zones, assigned by address. The standards are statewide; what changes by zone is the energy budget and several prescriptive requirements. Choose your zone for a plain-English summary.
For more on how climate shapes a report, see how climate zones affect Title 24.
How a Title 24 Report Shows You Meet the Requirements
A Title 24 report is prepared from your plans before the permit is issued. For homes and ADUs the main form is the CF1R. It lists the features your building must include and flags items that need HERS field verification. During construction, the installer documents what was installed, and the building inspector checks that the work matches the approved report.
Title24Comply prepares these reports online in CEC-approved compliance software, with standard turnaround of 2–3 business days and two revisions included. See pricing and order.
Frequently Asked Questions
Are Title 24 requirements the same everywhere in California?
The standards are statewide, but climate zone changes the energy budget and several prescriptive requirements. Some cities also adopt local ordinances that go further, so check with your building department.
Do mandatory measures apply if I use the performance method?
Yes. Mandatory measures apply under both methods. The performance method only allows trade-offs among features above those minimums.
Does every new home need solar panels?
Most newly constructed single-family homes do. There are exceptions, for example for some shaded sites, ADUs and additions. The report determines whether solar applies to your project.
Where can I find the exact numeric requirements for my project?
The exact values depend on your climate zone, project type and compliance method. They are set by the Energy Code and shown on your compliance forms once your project is modeled.
Do requirements change with each code cycle?
Yes. The code is updated about every three years. The cycle in effect when your permit application is submitted is the one that applies.
