Residential Quality HVAC

Residential HVAC

Codes and Standards Enhancement (CASE) Report

The Statewide CASE Team 2019 Title 24, Part 6 Final CASE Report is available below. The Final CASE Report incorporates feedback received during utility-sponsored stakeholder meetings, Energy Commission Pre-Rulemaking workshops, and personal communication with stakeholders. We encourage stakeholders to email feedback on the Final CASE Report to You can also participate in the 2019 Title 24, Part 6 Standards updated by attending the Energy Commission workshops and submitting written comments to the rulemaking docket. Refer to the Pre-Rulemaking and Rulemaking Workshop Notices for instructions on how to submit comments to the Energy Commission’s docket (available here).

Measure Description

This code change proposal includes one mandatory requirement, one compliance option, and one
alternative verification method. The measures affect single family and multifamily building types and
apply to all climate zones.

The proposed measures will:

  • Mandatory fan efficacy requirement: Reduce the maximum air handling unit fan efficacy
    currently required under Title 24 Part 6, 150.0(m)13 from 0.58 watts per cubic feet per minute
    (W/cfm) to 0.45 W/cfm.
  • Compliance option for fault detection and diagnosis (FDD) devices: Allow compliance
    credit for FDD devices that will support both the long-term, as well as initial, performance of
    cooling systems.
  • Alternative verification method (temperature split): Provide an alternate method to
    refrigerant charge verification that measures system performance and that can identify multiple
    system faults while reducing verification time.

The United States (U.S.) Department of Energy (DOE) adopted a new fan efficacy standard for
residential furnaces and certain other air handling equipment. The standard, which takes effect July
2019, will require maximum efficacies that will induce manufacturers to use fan motors that have
efficiencies consistent with brushless permanent magnet (BPM) motor types, enabling a reduction in the
current 0.58 W/cfm Title 24, Part 6 maximum efficacy to 0.45 W/cfm. Though the DOE standard does
not extend to heat pump or combined hydronic air handlers, the same Title 24, Part 6 limit is proposed
for furnaces, heat pumps, and hydronic air. Tables 150.0-2B and 150.0-2C will continue to provide an
alternative method of compliance to airflow-watt draw verification