Ask which voltage before you buy
This is the question that changes the size of the project, and it is routinely asked too late — after the appliance is chosen, when the electrical is treated as an implementation detail.
Most heat-pump water heaters are 240 volt and want their own dedicated circuit. If your panel has capacity and a spare space, that is straightforward. If it does not, that circuit is the thing that drags a panel or service upgrade into what you thought was an appliance swap.
The 120 VOLT models change that calculation. They run on an ordinary household circuit, which on a house with a small service can take the panel upgrade out of the project completely. Be clear-eyed about what you are trading: almost nobody installs these, and they recover noticeably more slowly, which a larger household will feel as running out of hot water. We would not put one in as a first choice. Where the honest comparison lands is a 120V model against a 240V model PLUS the electrical work it would require — and if that electrical work is a panel upgrade you did not otherwise want, the trade can be worth making. Decide it deliberately.
What the electrical work actually is
For a house switching from gas, the work is usually running a new circuit to somewhere that currently has no power at all. A gas water heater needs no supply, so there is often nothing at that location beyond perhaps a light.
- A LOAD CALCULATION first, ideally covering everything you intend to add rather than this appliance alone
- PANEL WORK if there is no spare capacity or no spare space — which is where a small project can become a larger one
- THE CIRCUIT ITSELF, sized for the model, from the panel to the location
- A DISCONNECT where required, and the terminations at the unit
- PERMIT AND INSPECTION coordination for the electrical scope
What determines the cost is the ROUTE. A location in a garage on the other side of the panel wall is a different job from one in a closet at the far end of a two-storey house with finished walls in between. That is worth establishing before the appliance is ordered, because it sometimes argues for a different location entirely.
Where the trade boundary sits
Worth stating plainly, because this project always involves two trades and the handoff is where time gets lost.
The WATER HEATER ITSELF, the plumbing, and capping or removing a gas line are C-36 plumbing work. They are not ours and we will not pretend otherwise. What we do is the electrical side: the load calculation, any panel or service work, the circuit, and the permit and inspection for that scope.
In practice the thing that makes these projects go smoothly is deciding the LOCATION jointly, up front. The plumber cares about the drain, the water lines and the gas cap. We care about the route from the panel. The manufacturer cares about air volume and clearances. Those three constraints intersect at one or two viable spots in most houses, and finding them on paper is far cheaper than discovering them with an appliance already delivered.
Why location matters more than you would think
A conventional tank is indifferent to where it sits. A heat pump is not, because it is a machine that moves heat out of the air around it.
- AIR VOLUME — it needs a certain amount of air to draw heat from, or ducting to somewhere that has it. The requirement is specific to the model, and the unit's own specification governs rather than any general rule
- COOL EXHAUST — it puts out air cooler and drier than it took in. Excellent in a garage. Unwelcome in a conditioned room you actually use
- NOISE — there is a compressor. It is not loud, but it is not silent, and it runs when it runs. Next to a bedroom wall is a decision people regret
- CONDENSATE — extracting heat from air produces water, which has to drain. A plumbing question that constrains placement, and therefore constrains the electrical run
- SERVICE ACCESS — filters and coils need occasional attention, so a location that requires moving three things to reach it is a location that will not get maintained
In most Santa Cruz homes the garage is the answer, and usually not as a compromise: the air volume is there, the cool exhaust is a non-issue, nobody is bothered by the noise, drainage is easier to arrange, and it is frequently closer to the panel than the alternatives.
Doing it alongside other work
A water heater is often the least urgent item on an electrification plan — until it fails, at which point it becomes the most urgent thing in the house. That asymmetry is worth planning around.
If other electrification work is planned, attaching this to it is materially cheaper: the panel work is shared, the permit process is shared, and running two circuits in one visit costs much less than two visits. If your existing water heater is old enough that it might fail before that work happens, it is worth deciding in advance what you would do — because the decision made in an emergency, with no hot water and a plumber on the phone, is usually a like-for-like gas replacement that closes off the electric option for another decade.
Heat-pump water heaters qualify for the federal efficiency credit that remains active, and they are one of the qualifying upgrades for GoGreen Home financing — which means panel work tied to installing one generally qualifies where the same work on its own would not. The current credit figures live on our tax credit guide rather than here, deliberately, because amounts change and one page carrying them is how they stay right.