Replacing a Packaged AC or Heat Pump Unit: What Title 24 Requires
A packaged unit is a complete replacement only when the ducts are replaced too. Swapped onto existing ducts it is an altered system, which brings duct sealing and, for heat pumps in every zone and air conditioners in zones 2 and 8 to 15, airflow and charge checks. A factory-charged package may skip field charge verification if the installer certifies it on the CF2R.
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Is your swap a complete replacement?
For an alteration, the Standards define an entirely new or complete replacement system as all the heating or cooling equipment, or a complete replacement of a packaged unit, plus an entirely new or replacement duct system (Section 150.2(b)1C). A new package on the old ducts is therefore an altered system, not a complete replacement. The manual adds that the ducts must be entirely new, even when under 40 feet long.
The factory-charge exception
Entirely new or complete replacement packaged systems that the manufacturer charged at the factory need no field charge verification. The installer certifies on the CF2R that the unit was pre-charged and not altered in a way that affects the charge, and the ECC-Rater does not verify it. Ducted systems still meet the airflow requirement where the type can be verified. The exception is worded for complete replacements, so ask your building department how it treats a unit-only swap.
Airflow
Where the rule applies (heat pumps everywhere, air-cooled air conditioners in zones 2 and 8 to 15), an altered system must show 300 cfm per ton or more, or 250 for small duct high velocity. A complete replacement without zoning dampers may instead meet Tables 150.0-B or 150.0-C through checks of the return duct and filter device (Section 150.2(b)1F).
Duct sealing numbers by situation
- Existing ducts: leakage of 10 percent of airflow or less, or 7 percent or less to outside; if neither is reachable, seal accessible leaks and pass a smoke test by an ECC-Rater.
- Entirely new duct system: 5 percent or less.
- Unit or ducts in a garage: 6 percent or less, or the smoke test, whatever the duct length.
- No test when the ducts were already sealed and documented, or total less than 40 linear feet.
Siting and forms
An outdoor condensing unit must sit at least 5 feet from any dryer vent outlet (Section 150.0(h)3), and a liquid line filter drier goes in if the manufacturer requires it. Give the installer the CF2R-MCH-01 series, CF2R-MCH-23-H for airflow and CF2R-MCH-25-H for charge.
Split systems are on the AC replacement checklist. Test detail: duct leakage, charge, airflow. A residential report covers the permit.
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
For an altered system the duct sealing is verified by an ECC-Rater, and the factory-charge route removes only the charge verification.
Only if the condensing unit sits at least 5 feet from its outlet. Otherwise move the unit or the vent.
Explore Air Conditioners
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