Specifying Rooftop Units for Title 24 Compliance

The California Code of Regulations has established standards for residential and commercial buildings within the California Energy Code. In Title 24, Part 6 of their Building Energy Efficiency Standards guide, the California Energy Commission outlines a list of requirements intended to reduce HVAC energy use. Many of these standards impact how a rooftop unit (RTU) should be configured in order to meet code.

Title 24 Requirements for Rooftops

The California Energy Commission maintains a list of RTU models they have certified. They also maintain a spreadsheet that lists the controllers which have been certified to meet Title 24 fault detection and diagnostics (FDD) requirements. In summary, the following conditions must be met in order for a rooftop unit to meet Title 24 requirements:

  • Return/Exhaust Option: exhaust fan or gravity damper
  • Economizer: full indoor air quality (IAQ) with full airflow measurement
  • CO2 sensor
  • Economizer Control: dry bulb sensor or single enthalpy sensor
  • Type of Damper: ultra-low leakage
  • No electric heat

The Importance of Proper Economizer Operation

For rooftop units, two of the most important aspects of Title 24 regulations are the requirements for ventilation and an associated fault detection and diagnostic system. Occupied buildings are required to provide either natural ventilation or mechanical ventilation. For a rooftop unit, this means an economizer is required. When functioning as designed, an economizer can be an excellent way to provide fresh air while minimizing energy use. But when they aren’t functioning correctly, economizers can also result in excess in energy use — by letting cold air in during the winter, or hot air in the summer. That’s why Title 24 also mandates that any RTU with a capacity of 4.5 tons or greater be fitted with a system that can monitor economizer operation and report any failures.

Correct economizer operation is just one facet of the complete Title 24 requirements. And while the detailed specifications for Title 24 compliance may seem complex, YORK® has a high-performance rooftop product portfolio with options to meet or exceed all Title 24 and related guidelines while providing class-leading, standard-efficiency levels. To learn more about Title 24 certification for rooftop units — including the specifics regarding ventilation, FDD and other requirements, download your free copy of the complete Variable Air Volume (VAV) Application Guide for Rooftop Units