Installing a Mini-Split Yourself: What Title 24 Still Requires
The Energy Standards care about who is responsible for the installation and signs the Certificate of Installation, and about who handles refrigerant. A DIY heat pump kit that arrives pre-charged still needs charge verification (as does an air conditioner kit in zones 2 and 8 to 15), only an EPA-certified technician may add or remove refrigerant, while permit questions and licensing questions belong to the building department.
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What the Energy Commission says about a DIY kit
The compliance manual takes this exact case in Example 4-17. A do-it-yourself split system still needs refrigerant charge verification where the alteration rules call for it (heat pumps in every zone, air conditioners in zones 2 and 8 through 15), even though it ships charged. Connecting the indoor unit, outdoor unit and charged line set at the home alters the factory charge, which disqualifies it from the packaged-system exception. The manual adds that a space-conditioning appliance other than a plug-in room unit needs a building permit and a load calculation, and that recovering the old system's refrigerant takes a technician with an EPA 608 Type II or Universal certificate.
The signature question
The Certificate of Installation is signed by the person in charge of the installation who is eligible under Division 3 of the Business and Professions Code to accept responsibility for it (Section 10-103(a)3). Signature authority can be handed to a representative only by a written agreement, and only where that law allows (Section 10-103(a)3A). Whether an owner qualifies is a licensing question for the building department, not something the Energy Standards settle.
Weigh-in is a skill, not a formality
- The person must be able to compute the charge from the manufacturer's standard amount and the line-set and coil adjustments, and to obtain an accurate weight (RA3.2.3.1.2).
- The electronic scale must read within 0.5 ounce or 0.5 percent and carry a calibration sticker (RA3.2.3.1.3 and RA3.2.3.1.4).
- Only the installer may weigh in. The ECC-Rater observes, may not add or remove refrigerant, and group sampling is not allowed.
What to take to the counter
Bring the model numbers, the load calculation, the line-set length and diameter, and a plan for who will recover or charge refrigerant. The installation checklist lists the steps a professional follows, finding an ECC-Rater explains who verifies, and the CF2R page covers the installer form. See also line set insulation. Reports start on the residential page.
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. Only an EPA-certified technician may add or remove refrigerant. The rater verifies and records the result, and a failed test goes back to the installer.
No. The factory-charged exception covers entirely new packaged systems. A split mini-split is completed at the home, so the charge route still applies wherever verification is required for that equipment and zone.
Explore Mini-Splits
- Mini-Split in a Garage, Shed or Workshop: Does It Trigger Title 24?
- Mini-Split Installation Title 24 Checklist
- Refrigerant Line Set Insulation on an AC or Mini-Split: What the Code Requires
- Replacing Ducted Central Air With Mini-Splits: What Title 24 Asks
- Cooling-Only Mini-Split or Heat Pump Mini-Split: What Triggers More?
View all Mini-Splits guides → · HVAC and Water Heating · Title 24 guide