Furnace Replacement Title 24 Checklist
A gas furnace swap replaces the system's air handler, so the connected ducts are sealed and tested by an ECC-Rater: 10 percent total leakage or 7 percent to outside. Furnace efficiency comes from the appliance rules, not the Energy Code. Only ducts under 40 linear feet, ducts already sealed and verified, or asbestos ducts skip the test.
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The checklist, in the order the job runs
- Efficiency. The Energy Code sets no furnace AFUE; the Appliance Efficiency Regulations in force when the permit is applied for do, and furnaces sold in California already meet them.
- Fuel. Replacement heating may not use electric resistance as the primary source (Section 150.2(b)1G). The manual's Example 9-42 refuses a gas furnace swapped for an electric wall heater.
- Combustion air and temperature rise. Combustion air follows California Mechanical Code Chapter 7 (Section 150.0(o)1K), and the furnace runs within the manufacturer's maximum temperature rise (Section 150.0(h)4A).
- Duct test. Example 9-41 treats a furnace blower as an air handler, so Section 150.2(b)1E applies.
- Thermostat. A setback thermostat is needed only if the system includes cooling and the old one is not a setback type (Example 9-38).
Setting the duct test target without a cooling coil
Leakage is a share of air handler airflow, and a heat-only system has no tonnage. Appendix RA3.1.4.2 allows 21.7 cfm for each kBtu/h of rated heating output, or a default of 0.5 cfm per square foot of floor. A furnace rated at 60 kBtu/h output gives 1,302 cfm, so 10 percent is about 130 cfm and 7 percent to outside about 91 cfm.
If the ducts will not pass
The installer seals every accessible leak, then the rater runs a smoke test and a visual check of boots, plenum and cabinet connections. Smoke only from the gasketed furnace cabinet does not fail it. A furnace or plenum in a garage carries 6 percent or a smoke test at any duct length, and a raised platform may not serve as a return plenum.
Paperwork and related pages
A changeout is documented on CF1R-ALT-02-E, the installer's test on CF2R-MCH-20-H and the rater's on CF3R-MCH-20-H. A new cooling coil added with the furnace is a separate trigger, in the air conditioner checklist. The general rule is on HVAC replacement, all triggers on duct leakage testing, and the counter question on the permit page. Start at HVAC contractors or residential.
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
No. Charge verification attaches to replaced refrigerant-containing parts under Section 150.2(b)1F, and a furnace has none. A new evaporator coil installed with it does.
The installer tests and an ECC-Rater, the role called a HERS rater until 1 January 2026, verifies. Results are registered, and a failure is corrected and retested.
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