The short answer
A heat pump needs one or more circuits sized from the numbers on its rating plate, a way to switch it off at the equipment, and a panel with room for the new load[1][2]. The equipment in the manufacturer manuals cited here runs on 208/230-volt or 208/240-volt single-phase power[1][2][7]. None of that comes from the size of the house or the tonnage in a brochure. It comes from the specific model your HVAC contractor selects.
That is why the equipment choice and the electrical plan are worth settling together, before anything is ordered. A heat pump moves heat rather than generating it, which is where its efficiency comes from, and the same equipment heats in winter and cools in summer[3]. The electrical has to suit both jobs.
Who does which part
Two California licence classifications meet on a heat pump job. The C-20 classification covers warm-air heating, ventilating and air-conditioning systems, including the air-conditioning unit, the ducts and the thermostatic controls[4]. The C-10 electrical classification covers the wires, apparatus and connections that use electrical energy[5].
In practice the HVAC contractor selects and sets the equipment, ducts and controls. We do the electrical side: the panel, the circuits, the disconnect and the connections at the equipment. The handoff between the two is the rating plate, so we ask for the model numbers before we quote.
The rating plate decides the circuit
The outdoor unit and the air handler each carry a rating plate with the electrical data the installer needs for the supply and its overcurrent protection[1][2]. Two numbers on it decide the circuit.
- MINIMUM CIRCUIT AMPACITY (MCA) sets the wire. The conductors have to be able to carry at least the MCA listed on the plate[1].
- MAXIMUM OVERCURRENT PROTECTION (MOP) caps the breaker. Daikin's air handler manual puts it this way: the breaker or fuse is sized larger than the MCA but must not exceed the MOP[1]. The breaker for your equipment comes from its own plate and manual.
- VOLTAGE is printed on the plate too[2].
The figures change from model to model. Daikin's instructions for one ducted heat pump series list a separate MCA and MOP for each capacity in the series[2], so the plate on your unit, not a rule of thumb, sets the breaker. Manufacturers can add their own limits too: Daikin's air handler manual asks for wire sized to allow no more than a 2% voltage drop from the panel to the unit[1], which matters on a long run to an attic or a garage.
How many circuits
In the Daikin ducted equipment cited here, the outdoor unit and the indoor air handler are separate pieces of equipment, each with its own supply. Your system's circuit count comes from its own equipment combination and manuals.
- THE OUTDOOR UNIT holds the compressor. Its supply is sized from its own rating plate[2].
- THE INDOOR AIR HANDLER has its own supply, sized from the air handler's plate. For the Daikin air handlers cited here, the rating plate gives the MCA for the air handler and its optional electric heat kit[1].
Mini-split and VRF equipment varies, and the installation manual settles it. Daikin's wall-mount mini-split manual says the power wire must not be connected to the indoor unit and calls for a separate power supply circuit for the outdoor unit[6]. Lennox's heat kit manual for its mini-split and VRF air handlers says the indoor unit and heat kit power should come through a breaker separate from the outdoor unit's[7]. Two arrangements, so we read the manual for the model you are actually getting.
Electric backup heat
Some air handlers can take a manufacturer-approved electric heat kit, sometimes called heat strips. Daikin's air handler manual says all electric heat is field installed and permits only its own approved kit series[1].
When a heat kit is included, the electrical has to be sized for the exact air handler and heat kit combination. For the Daikin air handlers cited here, the rating plate gives the MCA with the optional heat kit[1]. Some kits are two-circuit and need separate supply connections unless the manufacturer's single-point wiring kit is used[1]. And where supply wires are already in place, Lennox's manual says they have to be checked to make sure they are the proper size for the heater load[7].
Whether you need backup heat at all is an equipment-design decision, and it belongs to your HVAC contractor. What matters on the electrical side is knowing whether a kit is in the quote, and which size, before the circuit is designed.
A disconnect at the equipment
Whoever services the equipment needs to be able to switch it off where they are working. Daikin's instructions for its ducted heat pump outdoor units require a disconnect switch near the unit, and say not to mount it on the unit itself[2].
Indoors, Daikin recommends that an air handler installed without a heat kit has a field-supplied disconnect switch or breaker in its circuit, so the power can be shut off for service[1]. Where the disconnect goes is part of the electrical design, and we plan it with the equipment layout.
Will your panel carry it?
Whether your panel has room is answered by a load calculation, not by adding up nameplates. The County of Santa Cruz publishes a single-family load calculation worksheet that walks through the California Electrical Code's steps, and it lists air conditioning and electric heating together as noncoincident loads, counting the largest[8].
That matters for a heat pump, because one machine does both jobs. If you already have central air conditioning, the calculation was already counting a cooling load, and the question becomes how the heat pump's figures, including any heat kit, compare with it.
We run that calculation at the free inspection. If a heat pump is arriving alongside an EV charger or an induction range, run it once against everything you plan to add: our guide to that combination explains why, and the Panel Load Calculator walks the same standard-method steps.
"Heat pump ready" is a new-construction rule
California's 2025 Energy Code includes a requirement called heat pump space heater ready. Where a gas or propane furnace serves a dwelling, it calls for a dedicated 240-volt branch circuit within 3 feet of the furnace with conductors rated at 30 amps minimum, and a reserved space in the main panel for a future double-pole breaker[9].
It applies to newly built single-family homes[9]. The Energy Commission's own guidance says it does not apply to additions, alterations, or new buildings with all-electric appliances[10]. So adding a heat pump to an existing home, or altering one, does not trigger this rule. And a newer home that has the readiness circuit was built to a 30-amp minimum rather than to a particular heat pump[9], so the plate on the unit you choose still has to be checked against it.
Permits and the order of work
On our jobs, the HVAC contractor permits the mechanical work and we permit the electrical. Which building department issues the permit depends on your address. The cities of Santa Cruz, Capitola, Scotts Valley and Watsonville each run their own; unincorporated areas, including Live Oak, Soquel, Aptos and the San Lorenzo Valley, go through the County[11].
Order matters. If the panel needs an upgrade, that goes first. Then the circuits and the disconnect go in before the equipment arrives, so the HVAC contractor is not waiting on power on the day the system is set.
What to have ready
- The model numbers of the outdoor unit and the air handler or indoor heads, or the HVAC contractor's quote that lists them
- Whether an electric heat kit is included, and its size
- Where the outdoor unit and the indoor equipment will sit
- Anything else you expect to add in the next few years, such as an EV charger, an induction range or a heat-pump water heater