Heat Pump Hot Water and Your Switchboard: The Quiet Load Change Nobody Plans For

Does a heat pump hot water system need switchboard work? Usually yes, at least a new dedicated circuit, and sometimes more. A heat pump draws far less power than an old electric storage tank, but if you are coming off gas hot water it is a brand new electrical load your home never had, and it needs a circuit, protection and board space of its own. That is the step the rebate-driven installation rush most often skips or squeezes.

⚡ Quick Answers: heat pump hot water electrics

• How much power does a heat pump use? Far less than a resistive electric tank. Most residential units draw about as much as a small air conditioner while running.
• Do I need a new circuit? Yes, a hot water system should sit on its own dedicated circuit with its own protection, not share one with power points.
• Coming off gas? Then it is an added load: your switchboard needs a spare way, an RCD-protected circuit and enough spare capacity overall.
• Coming off an old electric tank? Easier: the existing hot water circuit can often be reused, and your total load usually drops.
• Off-peak or anytime? Heat pumps flip the old logic. Many run best in daytime warmth or on solar, so the controlled load question is worth an actual conversation.

1. The load itself: smaller than you think, newer than you think

Heat pumps move heat rather than generate it, which is why they use roughly a third or less of the electricity of an old resistive tank. The catch is the direction you are coming from. Replacing an electric storage tank with a heat pump reduces your load. Replacing gas adds a circuit that never existed, and it lands on a switchboard that may already be hosting new loads like an EV charger or air conditioning. Total headroom is a maximum demand question, and the calculator on this page gives you a quick read on where your home sits.

2. What the switchboard actually needs

• A dedicated circuit sized for the unit, protected by a safety switch, run to the new tank location.
• A spare way on the board. Plenty of older Sydney boards are physically full. If yours is a fuse board or already crammed, the heat pump can be the nudge that justifies a proper switchboard upgrade.
• An isolator at the unit so it can be serviced safely.
• A compliance certificate for the electrical work, which a licensed electrician must issue. If your installer cannot say who is doing the electrical side, that is your red flag.

3. Off-peak, controlled load and solar: the tariff decision

Old electric tanks lived on controlled load tariffs, heating overnight at cheap rates. Heat pumps change the equation: they work most efficiently in warmer daytime air, and if you have solar, running the heat pump in the middle of the day turns your excess generation into hot water. Some owners still choose controlled load for the cheap rate; others use a timer against their solar window instead. Our guide to which appliances suit off-peak power covers the trade-offs, and if you are weighing tariff options it helps to know your distributor first, so check your network area in seconds with our postcode checker.

4. The rebate rush: where corners get cut

NSW incentive schemes have made heat pump swaps cheap, sometimes near free, and volume installers price accordingly. The electrical scope is where those jobs get thin: circuits shared where they should be dedicated, no isolator, boards left without RCD protection, or no certificate issued at the end. The rebate paperwork is covered in the NSW Energy Savings Scheme guide; before you sign, ask three questions. Who is the licensed electrician on this job? Is the unit getting a dedicated RCD-protected circuit? Will I receive a certificate for the electrical work?

5. Part of a bigger picture: the all-electric home

Hot water is usually the first gas appliance to go, followed by cooking and heating. Each swap adds load, and homes that plan the sequence once, with the switchboard and supply sized for the end state, avoid paying for board work twice. If you are also eyeing an EV charger or ducted air conditioning, a power supply upgrade assessment now can save a second round of work later. Our hot water electrician guide covers the broader trade side of these jobs.

How High Demand Electrical helps

We do the electrical half of heat pump swaps properly: load check first, dedicated circuit and isolator, board tidy-up or upgrade where the install genuinely needs it, tariff and metering advice including smart meter upgrades, and a compliance certificate at the end. If a rebate installer has already been through and something feels off, an electrical safety inspection tells you exactly what was and wasn't done.

Heat Pump Hot Water FAQs (Sydney)

Can my existing off-peak hot water circuit be reused for a heat pump?

Often yes if you are replacing an electric tank, subject to condition and sizing. Coming off gas there is no circuit to reuse, so one gets added.

Will a heat pump overload my old switchboard?

The unit itself is a modest load, but a full or ageing board can still fail the spare-way and protection test. A quick inspection settles it before install day.

Do heat pumps work on single phase?

Residential units are overwhelmingly single phase. Three phase only enters the picture for large commercial systems.

Is the electrical work included in the advertised rebate price?

Sometimes, and sometimes only a minimal version of it. Ask for the electrical scope in writing, including the dedicated circuit and certificate.

Planning a heat pump swap? Get your switchboard and supply checked first or call 0402 559 777. Every job starts with a site assessment before scope and pricing are confirmed.