Navigating HERS Test Criteria for California Title 24 

As California pioneers advancements in energy conservation, the state’s building standards code, known as California Title 24, serves as a pivotal mechanism for curbing energy use in residential and commercial structures. A significant element of Title 24 is the HERS rating, an index utilized to gauge a structure’s energy efficiency. This article delves into the role of HERS testing in meeting Title 24 California requirements and its positive impact on builders, property owners, and the ecosystem.

What is a HERS Rating?

A HERS rating is a quantified assessment, given as a numerical value, that signifies the energy efficiency level of a building. The more energy-efficient a building is, the lower its HERS rating will be. The HERS test evaluates multiple aspects including wall insulation that complies with Title 24, windows that meet Title 24 specifications, climate zone-appropriate HVAC systems, residential lighting, and energy-efficient appliances. In this scoring system, a HERS rating of 100 serves as the benchmark, symbolizing a standard reference home, whereas a HERS score of 0 signifies a home that achieves zero-energy consumption.

Why is HERS pivotal for compliance with Title 24?

California’s Title 24 mandates a minimal degree of energy efficiency for all new constructions, gauged by the HERS index. HERS Ratings act as the state’s mechanism to verify if newly erected buildings conform to targeted energy performance criteria, thereby minimizing energy use and reducing greenhouse gas emissions.

Builders can leverage a low HERS Rating as a unique selling point, setting their constructions apart in the marketplace. Not only does this offer a competitive advantage, but it also assists builders in adhering to Title 24 California norms, averting potential legal repercussions and project delays.

For homeowners, a house with a low HERS rating translates into reduced energy bills and a more comfortable living space. Such energy-efficient homes are not only less expensive to run but also represent a wise long-term investment.

The Building Envelope as a Title 24 and HERS Consideration

In the grand scheme, the building envelope serves as a pivotal factor in meeting Title 24 requirements. Proper insulation techniques such as radiant barrier installation, meticulous air sealing, and the implementation of Title 24-compliant windows are all integral in curtailing energy loss and elevating a building’s overall energy efficiency. Utilizing electric tankless hot water heaters or electric on-demand water heaters can also contribute to a more favorable HERS Rating.

Comprehensive List of HERS Tests

The tests and verifications performed can vary depending on the nature of the residential project. The following are the key assessments that may be required:

Energy Efficiency in Ductwork

  • Duct Sealing: Ensuring all ducts are adequately sealed to prevent energy loss.
  • Supply Duct Dimensions, Surface Area, and Insulation Rating: Verifying that the ducts meet the specified surface area and insulation criteria.
  • Ducts with Minimal Leakage in Conditioned Spaces: Making sure ducts in conditioned areas are tightly sealed.

Title 24 HVAC Systems

  • Air Handlers with Low Leakage: Confirm that the air handlers are sealed properly.
  • Refrigerant Level in Ducted and Mini-Split AC and Heat Pump Systems: Check that the refrigerant charge is optimal.
  • Fan Efficiency in Air Handlers: Verifying that the fans in the air handlers are operating efficiently.

Ventilation and Airflow

  • Continuous Whole-Home Mechanical Ventilation Airflow: Ensuring that the ventilation system provides a continuous airflow.
  • Intermittent Whole-Home Mechanical Ventilation Airflow: Confirming intermittent airflow in the ventilation systems.

Insulation and Building Envelope

  • High-Quality Insulation Installation: Checking the quality of insulation installed.
  • Building Shell Air Tightness: Assessing how well the building’s envelope is sealed against air leakage.

Hot Water Systems

  • Verified Pipe Insulation Credit: Verifying the quality of pipe insulation.
  • Compact Hot Water Distribution System Verification: Ensuring the efficiency of hot water distribution.


  • Solar Panel Verification Protocol: Checking the installation and efficiency of solar panels.
  • Design of Multiple Recirculation Loops for Domestic Hot Water Systems in Multi-Unit Buildings: Inspecting the design of hot water systems in multi-unit residential buildings.

In summary, HERS Rating is an invaluable tool for ensuring new structures in California satisfy Title 24’s energy-efficiency prerequisites. This harmonizes with the interests of builders, property owners, and the broader environment by paving the way towards a more sustainable future. If you’re embarking on a new construction project or contemplating a remodel, it would be prudent to collaborate with a qualified HERS Rater to confirm Title 24 compliance and optimize your structure’s energy capabilities.