Title 24 vs HERS Testing — What’s the Difference and Why Both Matter in California
If you’re comparing Title 24 vs HERS testing, you’re likely trying to understand why your project needs both paperwork and field verification. Many homeowners, contractors, architects, and developers assume that once a Title 24 energy report is approved at plan check, the job is done. In reality, energy compliance in California often involves two connected—but very different—components: documentation and verification.
Understanding Title 24 vs HERS testing is essential for avoiding failed inspections, rework, and occupancy delays. Title 24 establishes the energy standards and modeling requirements. HERS testing verifies in the field that specific installed systems meet those modeled and required standards.
If you want help coordinating both documentation and verification requirements, call (626) 365-1518 to get started.
What Is Title 24?
When people say “Title 24,” they usually mean Title 24, Part 6 — California’s Building Energy Efficiency Standards. These regulations govern how energy-efficient a building must be in order to receive a permit.
Title 24 addresses:
- Insulation levels and envelope performance
- Window U-factor and SHGC values
- HVAC system efficiency requirements
- Water heating system performance
- Mechanical ventilation standards
- Lighting efficiency and controls (especially in commercial projects)
- Solar photovoltaic requirements for certain new homes
Title 24 compliance is demonstrated through documentation, typically generated using CEC-approved software when performance modeling is required.
What Is HERS Testing?
HERS stands for Home Energy Rating System. In California, HERS testing is a third-party field verification process required for certain energy measures under Title 24.
When comparing Title 24 vs HERS testing, think of it this way:
- Title 24: The design and documentation requirements.
- HERS testing: The field verification that confirms installation meets those requirements.
HERS testing may include:
- Duct leakage testing
- Refrigerant charge verification
- Airflow testing
- Fan efficacy verification
- Quality insulation installation verification
- Whole-house ventilation airflow verification
Not every project requires HERS testing, but many residential projects do—especially when HVAC systems or ducts are involved.
Title 24 vs HERS Testing — Key Differences
Understanding Title 24 vs HERS testing becomes clearer when you break down their roles.
1. Design vs Verification
- Title 24: Establishes energy design requirements and modeling assumptions.
- HERS testing: Confirms the installed systems meet those assumptions.
2. Timing
- Title 24: Completed before permit approval.
- HERS testing: Conducted during or after installation, before final inspection.
3. Documentation
- Title 24: Generates Certificates of Compliance (CF1R or NRCC forms).
- HERS testing: Produces verification documentation (CF3R forms) confirming field performance.
4. Who Performs the Work
- Title 24: Typically prepared by an energy consultant or qualified professional using approved software.
- HERS testing: Conducted by a certified HERS rater performing field measurements.
When Is HERS Testing Required?
In the Title 24 vs HERS testing discussion, one of the most common questions is whether HERS testing is mandatory.
HERS testing is often required for:
- New HVAC system installations
- Ducted heat pump systems
- Duct alterations or replacements
- Quality insulation installation verification
- Whole-house ventilation systems
Some smaller alterations may not trigger HERS testing, but many projects involving mechanical changes do.
Why Passing Plan Check Doesn’t Guarantee Passing HERS
One of the biggest misunderstandings in Title 24 vs HERS testing is assuming that approved paperwork guarantees field compliance.
A project can:
- Pass plan check with approved Title 24 documentation
- Install equipment that differs from the approved model
- Fail duct leakage testing
- Fail refrigerant charge verification
When installed systems do not match the modeled assumptions or fail performance thresholds, the project cannot receive final approval until corrections are made.
How Title 24 and HERS Work Together
Rather than separate requirements, Title 24 vs HERS testing are parts of a unified compliance system.
Title 24 establishes:
- Required efficiency levels
- Assumed system performance
- Mandatory measures
HERS testing confirms:
- The installation matches those requirements
- Performance meets minimum thresholds
- Field conditions align with documentation
When coordinated properly, the transition from modeling to verification is smooth.
Common Mistakes in Title 24 and HERS Coordination
Misunderstanding Title 24 vs HERS testing often leads to:
- HVAC substitutions not updated in the energy report
- Duct configurations that don’t meet modeled assumptions
- Missed verification triggers
- Scheduling HERS testing too late in the construction process
- Failure to provide required CF3R verification forms at inspection
Early coordination between the energy consultant, contractor, and HERS rater prevents these issues.
How to Ensure Smooth Compliance
To manage Title 24 vs HERS testing efficiently:
- Confirm required HERS measures during design.
- Align mechanical selections with energy modeling inputs.
- Schedule HERS verification before drywall closure when required.
- Update documentation if equipment changes occur.
- Keep communication open between all parties.
If your project has failed HERS testing or received compliance corrections, call (626) 365-1518, upload your plans via our contact page, or email info@title24energy.com with “Title 24 vs HERS” in the subject line.
We’re Ready To Take Your Call
Understanding Title 24 vs HERS testing ensures your project moves from design approval to final inspection without unexpected setbacks. Title 24 establishes energy compliance on paper; HERS testing verifies it in the field. Both must align for successful permit closeout.
Call (626) 365-1518 today to coordinate your energy documentation and verification requirements properly.
Frequently Asked Questions About Title 24 vs HERS Testing
1. Is Title 24 the same as HERS testing?
No. Title 24 sets energy standards; HERS testing verifies installation performance.
2. Do all projects require HERS testing?
No, but many residential HVAC-related projects do.
3. Does commercial construction require HERS?
Typically HERS is most common in residential projects, though certain measures may require verification.
4. Can I pass Title 24 but fail HERS?
Yes, if installed systems do not meet required thresholds.
5. What does duct leakage testing measure?
It measures air leakage from duct systems.
6. Who performs HERS testing?
A certified HERS rater conducts the field verification.
7. Are HERS documents submitted to the city?
Yes, verification forms are required for final approval.
8. Does Title 24 require modeling?
Performance compliance often requires modeling with approved software.
9. When should HERS testing be scheduled?
During construction, before final inspection.
10. What happens if HERS testing fails?
Corrections must be made and retesting scheduled.
11. Does HERS testing verify window performance?
No, window performance is documented under Title 24 modeling.
12. Are heat pumps subject to HERS verification?
Often yes, especially in new installations.
13. Does refrigerant charge require verification?
Yes, many systems require refrigerant charge testing.
14. Are ventilation systems tested?
Whole-house ventilation airflow may require verification.
15. Is insulation quality verified?
Certain projects require quality insulation installation verification.
16. Can documentation errors cause HERS issues?
Yes, mismatched documentation can complicate verification.
17. Is HERS part of plan check?
HERS is primarily a field verification process.
18. Do additions trigger HERS testing?
Often yes, when HVAC systems are altered.
19. Can coordination prevent failure?
Yes, early alignment between modeling and installation reduces risk.
20. How do I coordinate Title 24 and HERS testing?
Call (626) 365-1518 or submit your plans through our contact page to ensure both compliance and verification are properly handled.