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Residential HVAC Field Verification and Diagnostics


Measure Overview

Modifications and additions are proposed for the 2013 update cycle to improve Title 24 requirements, including the following:

  1. Require that a liquid line filter drier be installed and verified on air-cooled air conditioners and heat pump systems.
  2. Rename Charge Indicator Displays (CIDs) to Fault Indicator Displays (FIDs) to reflect that a broader range of devices can be submitted for approval with the CEC.
  3. Clarify that manufacturer installation specifications should be used, when available, as the basis for charge verification.
  4. Require that installers provide notice to homeowners that their units have not been verified of charge if outside temperatures are below 55ºF and the installer has charged the unit(s) using the weigh-in procedure, but has not used the HERS observation of weigh-in procedure for verification compliance.

The proposed changes will only modify existing code language, and will not modify the scope of the Standards. The only equipment required as a result of the standard are liquid line filter driers, which are regularly shipped and required for installation by manufacturers, and are easy to install. In addition to clarifying 2013 code language, the Statewide CASE Team developed a list of longer term code changes and associated research needs necessary for the 2019 Title 24 update cycle.

The Statewide CASE Team worked closely with the Western HVAC Performance Alliance (WHPA), an advisory group comprised of manufacturers, consultants, researchers, distributors, and contractors, to ensure that industry perspectives were understood. The WHPA was created by the California Utilities, California Public Utilities Commission, and the Western Cooling Efficiency Center (WCEC).

Stakeholder Meeting

Several stakeholder meetings and CEC staff workshops were held regarding the Residential HVAC Field Verification and Diagnostics building energy efficiency topic. The list of past meetings and hearings can be found here. If you would like to receive email updates on this CASE topic, click the link below.


  1. Final CASE Report