- Title 24 Part 6 is California’s mandatory energy efficiency standard, updated every three years by the California Energy Commission.
- MEP systems — HVAC, electrical lighting, and plumbing hot water — are the primary targets of Title 24 compliance requirements.
- The 2022 standards require all-electric readiness for new low-rise residential buildings and tighten heat pump water heater provisions.
- Duct leakage testing, HERS verification, and energy modeling with CEC-approved software are mandatory compliance steps.
- Budlong has navigated Title 24 compliance since the code’s inception in the 1970s, serving healthcare, education, aviation, and commercial sectors statewide.
- Non-compliance at permit or inspection stage can stall a certificate of occupancy and trigger costly redesigns.
- What Is California Title 24?
- How Title 24 Works: The Compliance Pathways
- Title 24 and the Three MEP Disciplines
- Key 2022 Standards Updates Affecting MEP
- Energy Modeling and Documentation Requirements
- Duct Leakage Testing and Field Verification
- Title 24 in Healthcare and Education Buildings
- Choosing a Title 24 MEP Engineering Partner
- Best Practices to Achieve First-Time Compliance
- Who Relies on Title 24 MEP Compliance Expertise?
- Related Reading
- Frequently Asked Questions
For any project breaking ground in California, the path from design concept to certificate of occupancy runs directly through Title 24. California’s Building Energy Efficiency Standards are among the most demanding in the nation, and the mechanical, electrical, and plumbing systems within a building carry the heaviest compliance burden. A missed compliance measure — an under-performing HVAC system, a lighting control gap, a failing duct leakage test — can halt construction, trigger expensive redesigns, and push project timelines well past their targets.
Budlong has engineered MEP systems under California’s energy code since its earliest form took shape in the 1970s. Over five decades of projects spanning health facilities, education campuses, aviation facilities, and commercial buildings have built an institutional understanding of how these standards are written, interpreted, and enforced at the plan check and inspection stages. This guide synthesises that experience into a practical resource for developers, architects, and building owners navigating Title 24 today.
What Is California Title 24?
California Code of Regulations Title 24 is the state’s comprehensive building standards code. It is divided into twelve parts covering everything from fire and life safety to disabled access to energy efficiency. When MEP engineers reference “Title 24,” they are almost always speaking specifically about Part 6: the California Building Energy Efficiency Standards, administered by the California Energy Commission (CEC).
Part 6 sets minimum energy performance requirements for new construction and significant alterations. It is divided into two major streams: residential standards (Part 6, Chapter 1) and nonresidential standards (Part 6, Chapter 4 and beyond). Both streams cover the building envelope, mechanical systems, electrical systems, and in the residential stream, plumbing hot-water systems as well.
Title 24 is not the same as the CALGreen code (Title 24 Part 11). CALGreen addresses green building practices more broadly — water efficiency, material waste, indoor air quality — while Part 6 focuses exclusively on energy. Both may apply to your project simultaneously.
The CEC updates the standards approximately every three years. The 2022 standards went into effect on January 1, 2023 and represent the current enforcement baseline. They introduced some of the most significant MEP-facing requirements in the code’s history, including all-electric readiness provisions for new residential construction and expanded solar and battery storage mandates.
How Title 24 Works: The Compliance Pathways
Title 24 provides two primary compliance pathways for nonresidential buildings and a similar structure for residential projects. Understanding which pathway applies to your project determines how your energy model is built and what documentation must accompany the permit application.
Prescriptive Compliance
The prescriptive path requires each building component to meet or exceed a fixed minimum standard. For HVAC, this means specified minimum efficiency ratings (EERs, COPs, or SEERs). For lighting, it means maximum lighting power density (LPD) values by space type. For the envelope, it means specified U-factors and solar heat gain coefficients. Prescriptive compliance is straightforward to document but leaves little flexibility for trade-offs between components.
Performance Compliance
The performance path requires demonstrating through CEC-approved energy simulation software that the proposed building uses equal or less energy than a reference building of identical size and occupancy built to prescriptive standards. This approach allows trade-offs — a highly efficient HVAC system can offset a less efficient envelope component, for example. Performance compliance requires more sophisticated energy modeling but often yields more cost-effective designs.
Key fact: The CEC estimates that the 2022 residential standards reduce energy use by approximately 30 percent compared to the 2019 standards, with new homes producing roughly 40 percent fewer greenhouse gas emissions than those built under 2019 requirements.
Title 24 and the Three MEP Disciplines
Title 24 touches mechanical, electrical, and plumbing engineering in distinct but interrelated ways. A coordinated MEP approach — where all three disciplines are designed with the energy model as a shared reference — is the most reliable path to first-time compliance.
Mechanical: HVAC Efficiency and Controls
Mechanical systems carry the largest compliance burden. Requirements include minimum efficiency ratings for air-cooled chillers, packaged rooftop units, heat pumps, and variable refrigerant flow (VRF) systems. The 2022 standards added heat pump water heater mandates for low-rise residential and expanded demand-controlled ventilation (DCV) requirements for high-occupancy nonresidential spaces. HVAC design must integrate economizer controls, occupancy-based setback, and in many cases, fault detection and diagnostics (FDD) for large commercial systems.
Electrical: Lighting Power Density and Controls
The electrical systems compliance scope under Title 24 centres on lighting. Indoor and outdoor lighting power density limits are defined by building type and space function. Mandatory lighting controls include occupancy sensors, daylighting controls (photosensors), and demand response capability for large nonresidential buildings. The 2022 standards also introduced requirements for EV charging-ready infrastructure and solar-ready panels in new residential construction, placing new design demands on electrical engineers.
Plumbing: Hot Water System Efficiency
Domestic hot water systems are regulated under Title 24 primarily in the residential stream. Requirements specify minimum energy factors for water heaters, pipe insulation standards, and — under the 2022 code — a mandate that new low-rise residential buildings include a heat pump water heater or be fully plumbed and wired for future heat pump water heater installation. Plumbing engineering must account for the electrical load implications of heat pump water heaters when coordinating with the electrical discipline.
Key 2022 Standards Updates Affecting MEP Design
The 2022 Title 24 cycle made material changes across all three MEP disciplines. Projects designed after January 1, 2023 must account for these provisions; projects permitted under earlier cycles may face compliance gaps if they move to alteration permits under the current code.
| Requirement Area | 2019 Standard | 2022 Standard | MEP Impact |
|---|---|---|---|
| Residential heat pump water heaters | Not required; gas allowed | HPWH or HPWH-ready wiring/plumbing required | Added electrical load; plumbing layout changes |
| EV charging infrastructure | EV-capable (conduit only) for some uses | EV-ready (outlet + wiring) for all new residential | Panel sizing, load calculations, dedicated circuit design |
| Nonresidential lighting | LPD values per 2019 table | Tightened LPD limits; expanded DCV requirements | More stringent fixture selection and control integration |
| HVAC fault detection and diagnostics | Optional for most systems | Mandatory for large packaged and VRF systems | Controls engineering scope increases |
| Solar PV + battery storage | Solar required for low-rise residential | Battery storage required alongside solar for residential | Electrical system integration with storage systems |
Navigating Title 24 Since the 1970s
Budlong has provided integrated MEP engineering services on thousands of California projects, from DSA-governed schools to HCAI-regulated hospitals. Our in-house commissioning capability means your Title 24 compliance model is verified against real-world system performance.
Energy Modeling and Documentation Requirements
Title 24 compliance documentation begins with a compliant energy model. For nonresidential projects using the performance compliance path, the energy model must be developed using software approved by the California Energy Commission — most commonly CBECC-Com for nonresidential or EnergyPro for residential projects.
Certificate of Compliance (CF1R / CF2R / CF3R)
The compliance documentation chain consists of three certificate types. The CF1R (Certificate of Compliance) is produced during design and submitted with the permit application. The CF2R (Installation Certificate) is completed by the installing contractor confirming each mandatory measure has been installed as specified. The CF3R (Inspection Certificate) is completed by a HERS rater after field verification. All three must be in place before a certificate of occupancy can be issued.
Mandatory Measures vs. Prescriptive Measures
A critical distinction in Title 24 is between mandatory measures and prescriptive measures. Mandatory measures apply regardless of compliance pathway — they cannot be traded off or averaged away. Examples include minimum insulation requirements, automatic shut-off controls for lighting, and outdoor air economizers above certain system sizes. Prescriptive measures can be substituted or traded off within the performance model. Failing to meet a mandatory measure is a compliance failure regardless of how well the building performs on other metrics.
The energy model is only as accurate as the inputs. When HVAC equipment is substituted during construction, the model must be updated and re-documented. Budlong’s integrated approach keeps design engineers and the commissioning team aligned throughout construction to prevent compliance gaps at final inspection.
Duct Leakage Testing and Field Verification
One of the most consequential — and most commonly failed — Title 24 field inspections is duct leakage testing. The code requires that new duct systems in conditioned spaces meet maximum leakage rates, typically expressed as a percentage of system airflow. For new residential construction, this threshold is generally 6 percent or less when tested to outside conditions.
Testing must be performed by a certified HERS rater using a duct blaster or calibrated fan pressurization equipment. The rater measures total leakage and leakage to the outside at system operating pressures. If the system fails, the contractor must seal the leaks and schedule a re-test. Projects that fail multiple tests face significant schedule impacts and can trigger additional plan check scrutiny.
In high-rise and complex commercial projects, duct leakage requirements apply to specific system types and installation conditions. Budlong’s mechanical engineers specify duct construction details, sealing methods, and access panel locations during design to reduce the probability of field failures before the HERS rater arrives on site.
Title 24 in Healthcare and Education Buildings
Healthcare and education buildings carry additional compliance complexity because they are subject to oversight by state agencies — the Department of Health Care Access and Information (HCAI) for healthcare and the Division of the State Architect (DSA) for K-12 schools and community colleges — in addition to local building departments. These agencies have their own plan review processes, and Title 24 compliance documents must satisfy both the local authority having jurisdiction (AHJ) and the state agency reviewer.
For health facilities, the former OSHPD (now HCAI) requires that all MEP systems meet not only Title 24 energy requirements but also HCAI’s own mechanical, electrical, and plumbing standards, which in many cases are more stringent. The interaction between HCAI ventilation requirements (minimum air changes per hour in clinical spaces) and Title 24 demand-controlled ventilation provisions must be resolved during design — typically by demonstrating that HCAI occupancy-based minimums are maintained even as Title 24 DCV controls modulate airflow.
For DSA-governed education projects, Title 24 compliance is reviewed as part of the DSA plan check process. DSA reviewers check that energy compliance documentation is consistent with the structural and architectural drawings — a coordination step that requires close communication between the MEP engineer and the project architect.
Choosing a Title 24 MEP Engineering Partner
Not all MEP engineers have equal familiarity with Title 24’s depth and enforcement nuances. The right partner has three distinguishing characteristics: integrated discipline coordination, in-house energy modeling capability, and direct experience with the specific agency pathway your project requires.
| Evaluation Criterion | Why It Matters | What to Ask For |
|---|---|---|
| In-house energy modeling | Prevents gaps between design intent and compliance model | Request sample CF1R and energy model outputs from similar projects |
| Healthcare or DSA experience | State agency reviewers require specific formatting and documentation | Ask for project lists by building type and agency path |
| Commissioning capability | Compliance gaps discovered at field verification are expensive; in-house Cx closes the loop | Confirm the firm provides functional testing, not just paperwork |
| Track record on similar scale | Title 24 complexity scales with building size and system type | Reference projects of comparable square footage and occupancy type |
Best Practices to Achieve First-Time Title 24 Compliance
Projects that engage MEP engineers at schematic design — not after the architect has fixed the envelope — have the best outcomes. Early coordination allows the energy model to inform equipment selection, duct routing, and control sequences rather than simply document them after the fact.
Align the Energy Model with Construction Documents
The compliance energy model and the construction documents must describe the same building. When equipment is substituted or layouts change during design development, the model must be updated. A model that does not match the CDs will fail plan check or, worse, will pass plan check but produce field failures during HERS verification.
Specify Duct Construction to Minimize Leakage
Duct sealing starts with the specification. Require mastic sealant at all joints and connections, specify UL 181B-listed tape for duct board systems, and include access panels at all accessible points. Avoid sheet metal screws without sealing — they are a common source of field test failures.
Commission Before the Inspector Arrives
Budlong’s in-house commissioning team performs pre-inspection functional testing to identify and resolve issues before the HERS rater or building inspector schedules their visit. This approach has prevented costly re-inspections on dozens of California projects.
Document Substitutions in Real Time
When the mechanical contractor substitutes equipment — as frequently happens in the current supply chain environment — document the substitution immediately. Verify that the new equipment meets or exceeds the efficiency ratings in the compliance model and update the CF2R accordingly. Undocumented substitutions are among the most common causes of compliance failures at final inspection.
- Title 24 Part 6 governs energy performance for mechanical, electrical, and plumbing systems in all new California construction.
- The 2022 standards introduced all-electric readiness, heat pump water heater mandates, and EV charging requirements that significantly expand MEP scope.
- Both prescriptive and performance compliance pathways are available; the performance path offers design flexibility but requires CEC-approved energy modeling software.
- Duct leakage testing by a certified HERS rater is mandatory for most new HVAC installations and is a common source of field failures.
- Healthcare (HCAI) and education (DSA) projects carry additional compliance complexity due to state agency review processes layered on top of local Title 24 enforcement.
- Engaging MEP engineers at schematic design, maintaining alignment between the energy model and construction documents, and commissioning before final inspection are the three practices most strongly correlated with first-time compliance.
Who Relies on Title 24 MEP Compliance Expertise?
Every California construction project is subject to Title 24, but the stakes — and the complexity — vary considerably by sector. Budlong serves owners and teams across the full range of project types where MEP compliance is most demanding.
Related Reading
Frequently Asked Questions
What is California Title 24 and which buildings does it apply to?
California Title 24, Part 6 is the California Building Energy Efficiency Standards. It applies to new construction and certain alterations of residential and nonresidential buildings statewide. It covers envelope, mechanical (HVAC), electrical lighting, and plumbing hot-water systems. Nearly every project that requires a building permit in California must demonstrate Title 24 compliance.
How often is Title 24 updated?
The California Energy Commission updates Title 24 standards on a roughly three-year cycle. The 2022 standards took effect January 1, 2023 and are the current enforcement baseline. Projects must comply with the standards in effect at the time of permit application, not at the time of design kickoff.
What is a CF1R form and why does it matter?
A CF1R (Certificate of Compliance) is the primary Title 24 compliance document submitted with permit applications. It documents how the project meets energy requirements and is generated using CEC-approved energy modeling software such as EnergyPro or CBECC-Com. Without an approved CF1R, the permit application is incomplete and will not be accepted by the local building department.
Does Title 24 require duct leakage testing?
Yes. For most new residential HVAC installations and many nonresidential alterations, Title 24 requires duct leakage testing by a certified HERS rater. Systems must meet maximum leakage thresholds — typically 6 percent of system airflow or less for new ducts. If the system fails, it must be repaired and re-tested before final inspection approval.
What MEP disciplines are most affected by the 2022 Title 24 update?
The 2022 update placed major new requirements on mechanical systems (heat pump readiness, expanded DCV, HVAC fault detection and diagnostics), electrical systems (EV charging-ready infrastructure, battery storage alongside solar), and plumbing (heat pump water heater provisions). Lighting power density limits were also tightened for nonresidential buildings, requiring more precise fixture selection and controls integration.
Can Budlong handle both the energy calculations and the construction documents?
Yes. Budlong provides integrated MEP engineering services that include Title 24 energy modeling, compliance documentation, construction documents, and field support through commissioning. This single-source approach eliminates gaps between the compliance model and as-built conditions — a common cause of field inspection failures on projects where separate consultants handle design and energy compliance.
What is a HERS rater and how do they relate to Title 24?
A California Home Energy Rating System (HERS) rater is a certified field verifier who performs mandatory third-party inspections and tests required by Title 24. These include duct leakage testing, refrigerant charge verification, airflow measurement, and other diagnostics that must be completed before final sign-off. HERS raters register their inspection results in the California Energy Commission’s HERS Registry, creating a permanent compliance record.
How does Title 24 interact with LEED or CALGreen compliance?
Title 24 sets the mandatory minimum energy floor. CALGreen Tier 1 and Tier 2 require additional energy reductions of 5 and 10 percent beyond the Title 24 baseline respectively. LEED’s energy credits use Title 24 as the baseline model for California projects. Meeting Title 24 is a prerequisite, not a substitute, for these programs. See MEP Design for LEED and CALGreen for details.
What happens if a building fails a Title 24 inspection?
If a mandatory measure fails inspection — such as a duct leakage test exceeding the permitted threshold — the contractor must repair or replace the failing system and schedule a re-inspection. Repeated failures can delay the certificate of occupancy, trigger additional review by the authority having jurisdiction, and generate financial penalties in some jurisdictions. Pre-inspection commissioning by Budlong’s team is the most effective way to avoid this outcome.
