The Title 24 Joint Appendices, JA1 to JA18
The Reference Appendices are the support documents for the Energy Code, in three sections: the Joint Appendices (JA), the Residential Appendices (RA) and the Nonresidential Appendices (NA). The Joint Appendices are the first. The 2025 edition has eighteen, JA1 to JA18, and the code points into them for data, tests and product qualification.
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- JA1 adds definitions to those in Section 100.1.
- JA2 is weather and climate data, including the 16 climate zones. See climate zones.
- JA3 defines the energy budget in long-term system cost and source energy.
- JA4 holds U-factor, C-factor and thermal mass data for assemblies.
- JA5 specifies occupant controlled smart thermostats. See smart thermostats.
- JA6 covers HVAC fault detection and diagnostic technology.
- JA7 sets data registry requirements, the rules behind CHEERS registration.
- JA8 qualifies high efficacy light sources. See JA8 lighting.
- JA9 qualifies low leakage air-handling units, and JA10 is the flicker test method.
- JA11 qualifies photovoltaic systems, and JA12 battery storage. See JA12 battery storage.
- JA13 covers heat pump water heater demand management, JA14 central heat pump water heater systems and JA15 central heat pump water heater readiness.
- JA16 gives criteria for pool and spa heating, and JA17 specifies fault indication displays for ventilation systems.
- JA18 sets the Guideline 36 programming library requirements.
How you meet them
Most readers never open a Joint Appendix. They meet one when a product or rule cites it: a lamp qualified under JA8, a battery under JA12, or a registered certificate under JA7. The code sections that cite them say what to provide, and how to read a CF1R walks through the certificate. The full text is in the Reference Appendices PDF, listed on the Title 24 code PDF page.
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- Title 24 Checklist: What to Have Ready Before You Order
- How to Read Your CF1R, Page by Page
- 15 Title 24 Mistakes That Trigger Plan Check Corrections
- How to Choose a Title 24 Consultant
Frequently Asked Questions
The Reference Residential Appendices and Reference Nonresidential Appendices, the other two sections of the Reference Appendices.
The Reference Appendices are adopted along with the Energy Code and contain the data and procedures that help builders comply.
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