Can I Swap My Central AC for a Heat Pump? What Title 24 Adds
A heat pump swap keeps the duct test and setback thermostat of an AC swap and adds items. Charge and airflow verification applies in every climate zone, not only zones 2 and 8 to 15, and the unit needs a 90-minute defrost delay, a backup-heat lockout above 35 F and, where backup heat exists, an outdoor-temperature thermostat.
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Your zone decides the first difference
Section 150.2(b)1Fii covers air-cooled air conditioners in zones 2 and 8 to 15 but air-source heat pumps in all zones, mini-splits included. In zones 2 and 8 to 15 the AC would have faced charge and airflow verification anyway. In zones 1, 3 to 7 and 16, swapping to a heat pump adds a test the AC would have skipped: airflow of at least 300 cfm per ton and a verified charge, with an ECC-Rater taking part.
What stays the same
Replacing the outdoor unit alone triggers duct sealing and verification at 10 percent total or 7 percent to outside (Examples 9-35 and 9-43), and refrigerant-part replacement means the thermostat becomes a setback type (150.2(b)1Fi). Heating can always be a heat pump; the fuel rule in 150.2(b)1G blocks only electric resistance as primary heat.
What the heat pump adds
- A defrost delay timer, where installer-adjustable, set to 90 minutes or more, except in zones 6 and 7 and in homes of 500 square feet or less in zones 3, 5 to 10 and 15 (150.0(h)6).
- Electric strip backup capped at 2.7 kW per nominal cooling ton, rounded up to the next kW (150.0(h)8).
- Locked-out backup heat above 35 F, with a thermostat that shows outdoor temperature and flags backup or emergency heat (150.0(h)7, 150.0(i)2).
The old furnace
If a gas furnace stays as backup, the same lockout and thermostat rules apply to it; the dual-fuel case is explained on heat pump with gas furnace backup.
Paperwork
The installer certifies the control tests on the CF2R, and the rater's verification is recorded on the CF3R. Forms are outlined on the HVAC replacement form page. For one complete job list, use the heat pump checklist; to compare with staying put, see whether a heat pump is required. Reports start at residential Title 24.
Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
Yes. Section 150.2(b)1Fii applies to air-source heat pumps in every climate zone.
Yes. The section names minisplit systems among the air-source heat pumps covered, though a system that cannot be verified by the specified procedures follows the alternative in Section 150.2(b)1Fiii.
Explore Heat Pumps
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- How Big Can a Replacement AC or Heat Pump Be Under Title 24?
- Title 24 Heat Pump Requirements for Homes
- Variable-Speed Heat Pump and a Smart Thermostat: Title 24 Rules
View all Heat Pumps guides → · HVAC and Water Heating · Title 24 guide