California’s Title 24 has shaped HVAC efficiency standards for more than a decade, and its influence continues to spread. Whether you are working in California or in a state adopting similar codes, understanding Title 24’s impact on economizers and ventilation control is essential.
This overview breaks down the key concepts behind Title 24 as they relate to economizers—without requiring you to navigate hundreds of pages of compliance documents.
What Is Title 24?
Title 24 is part of the California Code of Regulations and sets statewide energy efficiency and building performance requirements. It covers nearly every aspect of a building’s construction—including HVAC systems, ventilation strategies, and economizer performance expectations.
Although written for California, Title 24 often sets precedents that influence codes across the U.S.
Why Title 24 Matters in HVAC
Economizers play a major role in ventilation and outdoor air management. Title 24 directly addresses economizer performance, reliability, and energy impact. Its goal is simple:
Improve energy efficiency
Ensure proper ventilation
Reduce failures of economizer systems in the field
Historically, many economizers found in the field were non-functional, disconnected, or improperly configured, leading to wasted energy and poor indoor air quality. Title 24 was created to fix that.
Two Key Sections That Impact Economizers
Title 24 requirements fall into two major groups:
1. Mandatory Requirements — Section 120
This section requires fault detection and diagnostics (FDD) on economizer controllers.
This means the controller must:
- Detect component failures
- Identify sensor malfunctions
- Report specific error codes or alarms
- Indicate issues with actuator operation or damper positioning
The objective is to prevent unnoticed failures and ensure ongoing performance.
Examples of faults that must trigger an alert include:
- Failed or disconnected sensors
- Mixed air temperature out of expected range
- Damper not responding to command
- Economizer stuck open or closed
The core message: an economizer can no longer fail silently.
2. Prescriptive Requirements — Section 140.4
These are optional—unless your building is using the prescriptive compliance path.
Prescriptive requirements include:
- Tight limits on damper air leakage (≤10 CFM per square foot at 1″ w.c.)
- Minimum life-cycle durability (60,000 cycles)
- Minimum economizer warranty requirements
- Specific accuracy requirements for sensors
If a project meets overall energy goals through other means, these prescriptive items may not be required. But many owners and engineers voluntarily adopt them to achieve higher efficiency and long-term performance.
How Does Title 24 Compare to ASHRAE 90.1?
ASHRAE 90.1 is a national efficiency standard, but differs from Title 24:
|
Requirement |
Title 24 |
ASHRAE 90.1 |
|
Fault Detection |
Required |
Not required |
|
Outside Air Leakage |
≤10 CFM/sq.ft |
4–10 CFM/sq.ft |
|
Return Air Leakage |
Required |
Not specified |
|
Relief Air Leakage |
Not specified |
20–40 CFM/sq.ft |
|
Life-Cycle Testing |
Required |
Not specified |
Both aim for efficiency, but Title 24 is more stringent in fault detection and damper integrity.
Common Misconceptions About Title 24
Misconception #1: “Every economizer must meet all Title 24 requirements.”
Not true. Only mandatory requirements apply universally. Prescriptive items apply depending on the selected compliance path.
Misconception #2: “Field-installed economizers must be CEC-certified.”
False. Only factory-installed economizers go through CEC certification procedures. Field-installed equipment can be used as long as the system meets the mandatory requirements.
How Title 24 Affects Contractors and Building Owners
You may need to change your approach to:
- Economizer controller selection
- Sensor configuration
- Fault detection and monitoring
- Air leakage and damper performance
- Integration with building automation systems
Codes continue to evolve. Understanding Title 24 prepares you not just for California—but for future standards nationwide.
Final Thoughts
Title 24 reflects a larger shift in the HVAC industry: improving reliability, increasing ventilation control precision, and eliminating waste. Even if your state does not require Title 24 today, becoming familiar with these standards helps future-proof your knowledge and positions you to deliver better-performing systems.
As always, consult local building codes, engineers, and compliance professionals when designing or upgrading economizer systems.
If you have questions about economizers, ventilation controls, or related applications, MicroMetl’s technical support and customer teams are here to help.
