Title 24 is California’s mandatory building energy efficiency code. California requires a Title 24 compliance report for new construction, ADUs, room additions, and many alterations. Without it, the building department cannot issue your permit. This guide explains exactly what Title 24 is and what it means for your project.
Title 24 gets its name from Title 24 of the California Code of Regulations. Part 6 of Title 24 covers building energy efficiency. When contractors, architects, and building departments refer to Title 24, they mean Part 6 — the energy standards. California updates these standards roughly every three years. The current version is the 2025 California Building Energy Efficiency Standards, which took effect on January 1, 2026.
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Why Does California Have Title 24?
California created Title 24 energy standards in 1978 in response to the 1973 oil crisis. The goal was to reduce energy consumption in buildings. Buildings use approximately 25 percent of California’s electricity and 35 percent of its natural gas. The energy code raises the minimum performance floor for every new building constructed in the state.
The California Energy Commission manages the standards and updates them every three years. Each cycle raises the efficiency bar. The 2025 code is more demanding than the 2022 code. It is the most ambitious energy code California has ever adopted. It drives adoption of heat pumps, solar PV, and battery storage across California construction.
The long-term benefits add up. The California Energy Commission projects $4.8 billion in energy cost savings over 30 years. It also cuts greenhouse gas emissions by 4 million metric tons per year. That equals removing 900,000 cars from California roads.
What Does Title 24 Cover?
Title 24 covers six major systems in a building. Each system has minimum performance requirements. Your Title 24 compliance report shows your building department that your project meets the minimums for each applicable system.
| System | What Title 24 Regulates | 2025 Key Requirement |
|---|---|---|
| Building Envelope | Walls, ceilings, roofs, windows, doors | R-15 walls, R-38 ceilings, window U-factor ≤ 0.30 |
| HVAC | Heating, cooling, ventilation, duct systems | Heat pump baseline, duct leakage ≤ 5%, HERS verification |
| Water Heating | Water heater type, efficiency, and distribution | Heat pump water heater baseline for most homes |
| Lighting | Fixtures, controls, sensors, dimming | JA8 fixtures, occupancy sensors in all utility rooms |
| Solar PV | Rooftop solar photovoltaic systems | Mandatory for most new residential and commercial buildings |
| Battery Storage | Battery readiness wiring and panel capacity | Battery readiness required for most new homes |
Not every project triggers requirements for all six systems. A window replacement project triggers fenestration compliance. An HVAC replacement triggers mechanical compliance. A new home triggers all six. Your Title 24 report identifies which systems apply to your specific project scope.
Who Needs a Title 24 Report?
Any California building project that pulls a permit and involves energy systems needs a Title 24 compliance report. The following project types almost always require one.
New Home Construction
Every new single-family home in California needs a Title 24 new construction report. This applies to all permits submitted on or after January 1, 2026. The report must use current CEC-approved software and show compliance with the 2025 energy code. It covers the building envelope, HVAC, water heating, lighting, solar PV, and battery readiness. The report accompanies the permit application at plan check. See our new construction Title 24 service page for details.
ADUs, Granny Flats, and JADUs
All new ADUs, JADUs, granny flats, and in-law units require a Title 24 ADU report. The compliance path depends on how your building department classifies the project. A new detached ADU follows new construction rules. A garage conversion or attached ADU may follow alteration rules instead. We confirm the correct path before starting your report. See our ADU Title 24 service page for details.
Room Additions
A room addition that adds conditioned floor area triggers Title 24 compliance. All new walls, ceilings, and windows must meet current insulation and fenestration values. Any new HVAC or duct work in the addition must also meet the 2025 efficiency and leakage standards. See our room addition Title 24 service page for details.
Alterations and Remodels
Not every remodel needs a Title 24 report. However, these common alterations trigger one:
- HVAC replacement — replacing a furnace, air conditioner, or heat pump often requires load calculations, duct leakage testing, and a Title 24 alteration report.
- Window replacement — new windows must meet the 2025 U-factor minimums for your climate zone. This requires a fenestration compliance report.
- Water heater replacement — switching to a heat pump water heater triggers ventilation and electrical readiness requirements.
- Lighting changes — significant lighting scope changes in existing homes trigger lighting compliance documentation.
See our alteration Title 24 service page for more information.
Commercial Buildings
New commercial buildings, tenant improvements affecting HVAC or lighting, and large HVAC replacements all require commercial Title 24 forms. These we call them NRCC forms — Nonresidential Compliance Certificate forms. We prepare three types:
What Changed in the 2025 Title 24 Code?
The 2025 California Building Energy Efficiency Standards took effect on January 1, 2026. This is the most significant update to the code since 2019. Here are the five biggest changes.
Change 1
Long-Term System Cost Replaces TDV
California replaced the Time Dependent Valuation compliance metric with Long-Term System Cost (LSC). LSC measures the full 30-year lifecycle cost of energy use. Under LSC, heat pumps and all-electric systems score much better than gas systems. This change is why heat pumps are now the prescriptive baseline for most new homes.
Change 2
Heat Pump Baselines for Space and Water Heating
Heat pumps for both space heating and water heating are now the prescriptive baseline for most new single-family homes. Gas appliances remain an option under the performance path if your project meets the energy budget. However, the prescriptive path — the simpler option — now requires heat pumps as the default.
Change 3
Higher Insulation and Window Minimums
Wall insulation minimums increased to R-15 for 2×4 walls and R-21 for 2×6 walls. Cathedral ceilings now require R-38 across all climate zones. Window U-factor requirements tightened to 0.27 in several climate zones. These minimums are mandatory — you cannot trade them off against other systems.
Change 4
Solar PV Expanded to Commercial Buildings
Solar PV requirements now cover most new nonresidential buildings and high-rise multifamily projects. Previously these rules applied mainly to single-family homes. Commercial buildings must now install PV systems sized to a new formula based on occupancy type. Solar-ready provisions also apply to commercial projects where full PV may come later.
Change 5
Expanded HERS Verification and Duct Standards
More systems now require third-party HERS verification. Heat pump refrigerant charge verification is now mandatory in all climate zones. Maximum duct leakage tightened to 5 percent for single-family homes. All ducts in conditioned space must have R-6.0 insulation. The list of HERS-verified measures grew significantly compared to the 2022 code.
What Is a CF1R Report?
The CF1R is the Certificate of Compliance. It is the primary Title 24 document that accompanies your permit application. When your building department asks for a “Title 24 report,” they mean the CF1R. It shows that your project design meets all applicable energy code requirements for your climate zone and project type.
Title 24 Calcs prepares your CF1R using CEC-approved software updated to the 2025 code. We register the report with an approved HERS provider before we deliver it to you. This means it arrives ready to submit with your permit application. Most residential CF1R reports take 1 to 2 business days.
| CF1R Certificate of Compliance. Prepared by an energy consultant. Submitted with the permit application at plan check. | CF2R Certificate of Installation. Signed by the installing contractor in the field after each energy system is installed. | CF3R Certificate of Verification. Signed by a certified HERS Rater after field verification. Required before final inspection. |
The CF1R identifies which HERS measures apply to your project. The installing contractor completes the CF2R for each applicable system. The HERS Rater completes the CF3R after field verification. All three must register with an approved HERS provider before the building department issues a certificate of occupancy.
What Is HERS Testing?
HERS stands for Home Energy Rating System. HERS testing uses a certified third-party HERS Rater. The Rater visits your site. They confirm energy systems perform as your CF1R specifies. The California Energy Commission certifies HERS Raters and the organizations that manage the HERS rating program.
HERS testing happens in the field after installation. It must complete before the building department issues your certificate of occupancy. Your building department will not approve final inspection until the HERS Rater submits the CF3R. That certificate confirms all measures passed field verification.
Under the 2025 code, the following measures commonly require HERS verification:
- Duct leakage testing — confirms duct system leaks less than 5 percent of system airflow
- Heat pump refrigerant charge verification — now mandatory in all California climate zones
- Whole-house ventilation flow rate — confirms mechanical ventilation delivers required fresh air
- Envelope leakage testing — blower door test confirming building envelope air sealing where required
- Fault indicator display confirmation — heat pump and HVAC systems must include diagnostic displays
- Battery readiness panel verification — confirms electrical panel meets battery readiness requirements
- Pool pump controls — confirms variable speed pump controls are installed correctly
Your CF1R report lists the specific HERS measures that apply to your project. Not every project requires all measures. A window replacement project may require no HERS testing at all. A new home typically requires several measures. Your Title 24 report makes this clear before construction begins.
California Title 24 Climate Zones
California uses 16 Title 24 climate zones. Your zone sets the insulation values, window minimums, solar PV sizing, and HVAC thresholds for your project. Using the wrong climate zone is one of the most common causes of plan check rejections and corrections.
Your climate zone depends on your project address. It does not depend on your city or county. Some cities fall across multiple climate zones. The California Energy Commission climate zone tool can confirm your zone by zip code. We confirm your exact zone by parcel address before starting any report.
| Zone | Key Areas | Climate Character |
|---|---|---|
| Zone 6 | Coastal LA, Orange County coast, San Diego coast | Mild marine. Low heating loads. Strict window requirements. |
| Zone 7 | Most of San Diego County, Chula Vista, Carlsbad | Mediterranean. Moderate climate. Balanced heating and cooling loads. |
| Zone 8 | Inland OC, Irvine, Anaheim, most of Orange County | Warmer inland. Higher cooling loads than Zone 6. |
| Zone 9 | San Fernando Valley, Burbank, Pasadena, inland LA | Hot summers. High cooling loads. More demanding HVAC requirements. |
| Zone 10 | Riverside, San Bernardino, Corona, Temecula, Fontana | Hot inland. Very high cooling loads. Demanding insulation requirements. |
| Zone 12 | Sacramento Valley, Sacramento, Elk Grove, Roseville | Hot dry summers and cold winters. Dual season demands. |
| Zone 13 | Fresno, Bakersfield, San Joaquin Valley south | Extreme summer heat and cold winters. Most demanding dual-season zone. |
| Zone 15 | Palm Springs, Palm Desert, Coachella Valley | Extreme desert. Highest cooling loads in California. |
See our California Title 24 climate zones guide for all 16 zones.
Prescriptive vs. Performance Compliance
Title 24 offers two compliance paths. Both are valid. The right choice depends on your project design and goals.
| Factor | Prescriptive Path | Performance Path |
|---|---|---|
| How it works | Follow a fixed checklist of minimum measures | Model the building and meet an overall energy budget |
| Heat pumps | Mandatory in most cases | Not mandatory if energy budget is met |
| Flexibility | Low — follow the checklist | High — trade off between systems |
| Complexity | Lower | Higher |
| Best for | Standard new homes and ADUs | Room additions, remodels, and complex designs |
| Software | Required in some cases | Always required — CEC-approved software only |
The performance path works well for room additions and remodels where installing a heat pump is not practical. It lets your project meet the energy budget through other efficiency improvements. Title 24 Calcs works with both paths and recommends the best option for each specific project.
How Much Does a Title 24 Report Cost?
Title 24 report costs vary by project type and complexity. At Title 24 Calcs, residential reports start at $250. This includes the CF1R report, HERS registration, plan-sized PDFs, and revision support.
| Residential Reports New homes, ADUs, room additions, and alterations. Starting at $250. Most reports ready in 1–2 business days. | Commercial Reports NRCC-ENV, NRCC-MCH, and NRCC-LTI forms for nonresidential projects. Quoted by scope. Most ready in 2–3 business days. |
Title 24 report costs are typically a small fraction of total permit and construction costs. A $400,000 room addition might need a $350 Title 24 report. That is less than 0.1 percent of project cost. A missing or incorrect Title 24 report can delay your permit. That delay costs far more than the report itself.
See our full pricing page for current rates by project type.
Common Title 24 Mistakes That Cause Plan Check Rejections
These are the most common reasons California building departments send plan check corrections related to Title 24.
- Wrong climate zone — using Zone 9 for a project that falls in Zone 10. This produces incorrect insulation, window, and solar PV specifications that do not match what the building department expects.
- Outdated software — using 2022-code software for a permit submitted on or after January 1, 2026. Building departments now check for the 2025 code version identifier on the CF1R.
- Missing HERS registration — submitting a CF1R that has not been registered with an approved HERS provider. Most California building departments require the registered version, not just the PDF.
- Undersized solar PV — using the wrong formula or climate zone capacity factor to size the solar system. This is especially common in Zone 15 desert projects where the PV requirement is larger than in coastal zones.
- Missing battery readiness documentation — omitting the battery readiness panel schedule or load calculations that the 2025 code now requires for most new homes.
- Wrong compliance path for ADUs — applying new construction rules to a garage conversion that should follow alteration rules, or vice versa. The wrong path produces incorrect HERS measures and mandatory equipment specifications.
Frequently Asked Questions About Title 24
Is Title 24 the same as an energy audit?
No. A Title 24 compliance report is not an energy audit. An energy audit evaluates how an existing building currently performs. A Title 24 report shows that a proposed project will meet California’s minimum energy standards if built as designed. Building departments require it before issuing a permit — not after construction.
Does Title 24 apply to my project if I do not pull a permit?
Title 24 applies whenever a permit applies. No permit required means no Title 24 report required in most cases. Unpermitted work that alters energy systems can create disclosure obligations at sale. It may also create contractor liability. Always confirm with your local building department.
Can I use a 2022 Title 24 report for a permit submitted in 2026?
No. The 2025 code applies to all permits submitted on or after January 1, 2026. A report prepared under the 2022 code will not show compliance with the 2025 standards. California building departments now check for the 2025 code version identifier on the CF1R. A 2022-code report will result in a plan check correction and delay your permit.
How long does it take to get a Title 24 report?
Title 24 Calcs delivers most residential reports within 1 to 2 business days. Commercial reports take 2 to 3 business days depending on scope. Rush options are available for urgent permit submittals.
What do I need to provide to get a Title 24 report?
For residential projects: floor plan, exterior elevations, window and door schedule, equipment types, and project address. For commercial projects: floor plan, elevations, mechanical plan, lighting plan, and equipment schedules. More complete plans mean faster delivery.
Does Title 24 apply to manufactured homes and mobile homes?
Manufactured homes and mobile homes follow separate federal HUD standards, not Title 24. However, site-built additions to manufactured homes typically follow Title 24. Confirm with your local building department for your specific situation.
Is Title 24 only for new construction?
No. Title 24 applies to many alterations and additions as well. HVAC replacement, window replacement, and room additions can all trigger Title 24. Commercial tenant improvements may trigger it too. The scope of the report depends on what systems fall within the permitted scope of work.