Heat Pump Water Heater Circuit
Heat Pump Water Heater Circuit: Breaker, Wire & the 120V Shared-Circuit Rule
The breaker and wire every major heat pump (hybrid) water heater line needs, transcribed from each manufacturer's own spec sheet, with the NEC math that decides whether the new 120V plug-in class can share a circuit.
The Four Circuit Types
Heat pump water heaters ship in four circuit archetypes, and the model-number suffix usually encodes which one you have. Two are new with the 120V plug-in product class; two are the familiar 240V dedicated circuits.
| Circuit type | Example line | Breaker | Conductor | Ground |
|---|---|---|---|---|
| 120V shared circuit | Rheem ProTerra Plug-in Heat Pump with HydroBoost (Shared Circuit) | 15A / 120V | #14 Cu | #14 Cu |
| 120V dedicated circuit | Rheem ProTerra Plug-in Heat Pump (Dedicated Circuit) | 15A / 120V | #14 Cu | #14 Cu |
| 240V dedicated (mainstream) | Rheem Performance Platinum ProTerra Hybrid (30A) | 30A / 240V | #10 Cu | #10 Cu |
| 240V dedicated (low-amp) | Rheem Performance Platinum ProTerra Hybrid (Low-Amp, 15A) | 15A / 240V | #14 Cu | #14 Cu |
The GE Profile GeoSpring 120V Plug-in (FlexCapacity) is a fifth variant: the manufacturer lists it for a shared 120V circuit, a dedicated 120V circuit, or conversion to 240V; follow the configuration on its rating plate. Breakers are the manufacturer-stated values; conductors and grounds derive from the stated breaker.
Can a 120V Heat Pump Water Heater Share a Circuit?
This is the genuinely new electrical question the 120V plug-in class created, and the NEC answers it with arithmetic. NEC 210.23(B)(2) limits utilization equipment fastened in place to 50% of a 15A or 20A multi-outlet branch circuit (a plumbed, mounted water heater is fastened in place even when it is cord-and-plug connected). A fixed storage water heater 120 gallons or less is also a continuous load sized at 125% (NEC 422.13), which reduces that 50% ceiling to 40% of the circuit rating: 6A on a 15A circuit, 8A on a 20A circuit.
The listed shared-circuit model clears it: 3.67 A <= 6 A (15 A x 50% / 1.25 = 6 A); listed by the manufacturer for shared-circuit use.
The dedicated plug-in model does not get the allowance: The manufacturer requires a dedicated circuit; a general-purpose circuit tops out at 6 A (15 A x 50% / 1.25 = 6 A).
A listed unit may be cord-and-plug connected under NEC 422.16(A). This whole question applies only to the 120V plug-in class: a 240V hybrid is always installed on its own dedicated circuit.
Circuit Specs by Model Line
The breaker, wire, and shared-vs-dedicated verdict for each line, transcribed from the manufacturer's spec sheet with the source linked.
Rheem ProTerra Plug-in Heat Pump (Dedicated Circuit)
120V plug-in, 15A breaker on #14 Cu.
Rheem ProTerra Plug-in Heat Pump with HydroBoost (Shared Circuit)
120V plug-in, 15A breaker on #14 Cu.
GE Profile GeoSpring 120V Plug-in (FlexCapacity)
120V plug-in, 15A breaker on #14 Cu.
Rheem Performance Platinum ProTerra Hybrid (30A)
240V dedicated, 30A breaker on #10 Cu.
Rheem Performance Platinum ProTerra Hybrid (Low-Amp, 15A)
240V dedicated, 15A breaker on #14 Cu.
A.O. Smith Voltex AL (Anti-Leak) Hybrid
240V dedicated, 30A breaker on #10 Cu.
A.O. Smith Voltex Hybrid (HPTU, prior generation)
240V dedicated, 30A breaker on #10 Cu.
State ProLine XE Voltex Hybrid
240V dedicated, 30A breaker on #10 Cu.
Bradford White AeroTherm (RE Series) Hybrid
240V dedicated, 30A breaker on #10 Cu.
GE Profile GeoSpring 240V (FlexCapacity)
240V dedicated, 30A breaker on #10 Cu.
Breaker & Wire Summary
| Model line | Circuit | Breaker | Conductor |
|---|---|---|---|
| Rheem ProTerra Plug-in Heat Pump (Dedicated Circuit) | 120V plug-in | 15A | #14 Cu |
| Rheem ProTerra Plug-in Heat Pump with HydroBoost (Shared Circuit) | 120V plug-in | 15A | #14 Cu |
| GE Profile GeoSpring 120V Plug-in (FlexCapacity) | 120V plug-in | 15A | #14 Cu |
| Rheem Performance Platinum ProTerra Hybrid (30A) | 240V dedicated | 30A | #10 Cu |
| Rheem Performance Platinum ProTerra Hybrid (Low-Amp, 15A) | 240V dedicated | 15A | #14 Cu |
| A.O. Smith Voltex AL (Anti-Leak) Hybrid | 240V dedicated | 30A | #10 Cu |
| A.O. Smith Voltex Hybrid (HPTU, prior generation) | 240V dedicated | 30A | #10 Cu |
| State ProLine XE Voltex Hybrid | 240V dedicated | 30A | #10 Cu |
| Bradford White AeroTherm (RE Series) Hybrid | 240V dedicated | 30A | #10 Cu |
| GE Profile GeoSpring 240V (FlexCapacity) | 240V dedicated | 30A | #10 Cu |
Full chart with wattages, amps, and grounds: heat pump water heater amps chart. Class comparison: 120V vs 240V.
Frequently Asked Questions
What size breaker for a heat pump water heater?
A mainstream 240V hybrid takes a 30A double-pole breaker on a dedicated 240V circuit with #10 copper, the same circuit a standard 4,500W resistance tank uses (18.75A at 240V, sized at 125% as a continuous load to 23.44A per NEC 422.13). The new 120V plug-in class takes a 15A / 120V circuit instead, and low-amp 240V lines like the Rheem H22 series take a 15A / 240V circuit. Under NEC 422.11(E) the breaker must not exceed the rating marked on the appliance, so the nameplate always governs.
How many amps does a heat pump water heater use?
A 240V hybrid with a 4,500W backup element draws 18.75A at 240V with the element on (amps = watts / volts); as a continuous load the circuit is sized at 125%, 23.44A (NEC 422.13). In heat-pump mode it draws only a few amps; the circuit is sized for the element. A 120V plug-in unit like the Rheem HydroBoost shared-circuit model averages about 440W, roughly 3.67A, because it has no resistance element.
Can a 120V heat pump water heater share a circuit?
Only if the manufacturer lists it for shared-circuit use. NEC 210.23(B)(2) limits utilization equipment fastened in place to 50% of a 15A or 20A multi-outlet circuit, and the 125% continuous sizing for a storage water heater (NEC 422.13) reduces that to 40% of the rating: 6A on a 15A circuit, 8A on a 20A circuit. For the listed HydroBoost model: 3.67 A <= 6 A (15 A x 50% / 1.25 = 6 A); listed by the manufacturer for shared-circuit use. The shared-circuit question applies only to the 120V plug-in class; a 240V hybrid is always on its own dedicated circuit.
Do I need a dedicated circuit for a heat pump water heater?
Every 240V hybrid needs a dedicated 240V circuit; each 240V line on this page states one on its manufacturer spec sheet. In the 120V plug-in class it depends on the model: the Rheem dedicated plug-in requires its own 15A / 120V circuit even though it uses a standard plug, while the HydroBoost shared-circuit model and the GE Profile FlexCapacity unit are listed for shared-circuit use. A listed unit may be cord-and-plug connected under NEC 422.16(A).
120V vs 240V heat pump water heater: what is the wiring difference?
A 120V plug-in unit runs on a 15A / 120V circuit with #14 copper, plugs into a standard outlet, and recovers more slowly because it has no large resistance element. A 240V hybrid takes a dedicated 30A / 240V circuit on #10 copper (15A on #14 for the low-amp lines), wires like a standard electric tank, and recovers faster on its 4,500W backup element. Never put a 240V hybrid on a shared circuit, and never assume a 120V unit needs a 240V run.
Intry VerifiedA worked default reading, traceable end to end: what it was calculated from, what it was run with, how it was checked, and who has final say.
Where this number comes fromIntry Verified
- Calculated from
- NEC 422.13 (continuous), 310.16, 240.4(D), 250.122
- Run with
- Unit240V hybrid (4,500W element)
- Element4,500 W
- Supply240 V, 1-phase
- Load typeContinuous (422.13)
- Checked
- Every published figure is re-derived from its locked source before any deploy, backed by 1964 automated checks that also guard where each number comes from. A number that drifts from the cited NEC section blocks the ship. This is our own deterministic gate, not a third-party audit.
- Final say
- The unit nameplate has the final say on the breaker; your AHJ and local amendments govern the install.
Intry Verified · NEC 2023 · Build 2786BE1 · 2026-07-11
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