2025 CalGreen: Replacing A/C Condenser with Heat Pump

The City of Menlo Park has adopted a local amendment that adds §4.507.3 to the 2025 California Green Building Standards Code (CALGreen) (Muni Code § 12.18.110). The added section establishes the requirement for a heat pump to be installed in lieu of air conditioning condensing unit when the proposed project scope includes the replacement/upgrade of an existing air conditioning condensing.

Please refer to Muni Code §12.18.110 for specific requirements.

The following are two exceptions to the added sections:

1. When the differential cost between an air conditioner condensing unit and a heat pump condensing unit(s) exceeds 20% of the cost of construction, the heat pump is not required to be installed; 
   Note: A completed the AC to HP Unreasonable Hardship Form is required to be included as part of the required permit applications documents when applying this exception.
2. Unless already required by the 2025 California Energy Code due to the proposed work scope, an air conditioning condensing unit can be used when the following requirements are met:

• Systems with existing duct distribution system: The system shall meet the airflow and refrigerant charge verification requirements of §150.2(b)1Fii; or 
• Systems with entirely new or complete replacement duct distribution system: R-8 duct insulation shall be installed for all new ducts located in unconditioned space;
• The duct system measured air leakage shall be equal to or less than 5% of the system air handler airflow as confirmed through field verification and diagnostic testing, per the requirements in Title 24, Part 6, Reference Residential Appendix §RA3.1.4.3.1. If it is not possible to meet the duct sealing requirements, all accessible leaks shall be sealed and verified through a visual inspection and a smoke test by a certified ECC-Rater utilizing the methods specified in Reference Residential Appendix §RA3.1.4.3.5;
  
  Note: This is not required when documentation is provided verifying the existing duct systems are constructed, insulated or sealed with asbestos by a licensed asbestos abatement contractor.
  
  
• Install a system thermostat that conforms to the specifications in §110.12 of the California Energy Code.