HEAT PUMP INSTALLATION IN TUSTIN, CA

Tustin is inland, away from the beach cities. NOAA explains that the marine layer forms when cold ocean water cools the air above it, and that its depth changes with the weather, so a deeper layer can move farther inland. The National Weather Service in San Diego says the weather can be very different between beaches and inland areas.

That is why we size a heat pump from the house rather than the zip code. Windows, sun exposure, insulation and ductwork decide how hard the system works on a warm afternoon and on a cool night, and the assessment looks at each.

• NOAA JetStream: The Marine Layer (opens in a new tab)
• National Weather Service San Diego: The Weather Guide, 6th Edition, 2012 (PDF) (opens in a new tab)

Wherever you live, the same state rules shape a heat pump changeout. CSLB's HVAC checklist tells homeowners to make sure the contractor obtains a building permit and that the building department performs all required inspections. The California Energy Commission's 2025 Energy Code, which applies to buildings whose permit applications are applied for on or after January 1, 2026, adds testing to the permit.

• Duct sealing and verification: the Energy Commission says replacing the outdoor unit or the indoor unit of a split system, by itself, triggers duct sealing and field verification. An independent rater, called an ECC-Rater, verifies the result.
• Refrigerant charge: the Commission's compliance manual calls for refrigerant charge verification on heat pumps in all climate zones. For air conditioners it applies in climate zones 2 and 8 through 15.

Which tests apply depends on the equipment and your address. We do not assign climate zones to cities, so ask your contractor or building department which zone your address is in and which of these tests apply.

• CSLB: HVAC Installation Fact Sheets and HVAC Checklist for consumers (PDF) (opens in a new tab)
• California Energy Commission: 2025 Building Energy Efficiency Standards (opens in a new tab)
• California Energy Commission: 2025 Single-Family Heating, Ventilation, and Air Conditioning (HVAC) (opens in a new tab)
• California Energy Commission: 2025 Single-Family Residential Compliance Manual, Chapter 9 (alterations and repairs to existing homes) (opens in a new tab)

The city has a Historic Preservation page and a Tustin Historic Resources Survey page. A heat pump's outdoor unit and the refrigerant lines that connect it to the indoor equipment can show on the outside of a house, so if your home is an older one, ask the city whether either page applies to your address before the plan is final.

• City of Tustin: Historic Preservation (opens in a new tab)
• City of Tustin: Tustin Historic Resources Survey (opens in a new tab)

We have not confirmed whether any specific Tustin address is listed in the survey or subject to preservation review. Ask the city.

If your home is in a homeowners association that requires approval for physical changes, Civil Code Section 4765 sets the ground rules for that review: the association's decision is to be in writing, and a disapproval has to explain why and describe how to ask for reconsideration. HOA approval and a city permit are separate. One does not replace the other.

Send the association the same drawings you give the Building Division, so the two approvals describe the same equipment. If the plans change after one of them signs off, tell the other before work starts.