Heat Pump Hot Water Systems: What Melbourne Homes Need Electrically

Heat pump hot water systems have become one of the most common upgrades in Melbourne homes, driven by Victorian rebates and running costs significantly lower than traditional electric storage. But most homeowners researching them focus entirely on the unit and the plumbing — and completely overlook the electrical side, which is where installations most commonly go wrong or hit unexpected costs.

A Licensed Electrician Is Legally Required

This isn't optional or a best-practice recommendation. According to Energy Safe Victoria, installing the wiring, RCD protection, and isolator for a hot water service must be carried out by a person holding an A-class electrical licence working under a Registered Electrical Contractor. Disconnecting and making safe the wiring on your old system falls under the same requirement. If you're organising a heat pump installation through a plumber or supplier, confirm a licensed electrician is doing the electrical portion.

RCD Protection Is Mandatory

Under AS/NZS 3000:2018, RCD protection is required on the circuit supplying a heat pump hot water system. This is one of the most common compliance failures found during inspections of heat pump installations — systems installed without proper residual current device protection. When a new circuit is installed for a heat pump, or an existing hot water circuit is upgraded, a Type A RCD is required. Older Type AC RCDs are no longer permitted for new installations in Australia.

Dedicated Circuit and Manufacturer Specifications

Under the Wiring Rules, a hot water service must be installed in accordance with the manufacturer's instructions — which means if the manufacturer specifies a dedicated circuit, or a particular cable size beyond the standard minimum, that specification must be followed. This is why a proper electrical assessment matters before installation: the requirements vary by unit, and assuming a generic setup will work can result in a non-compliant installation.

Replacing a Gas System? Expect Additional Work

If you're moving from gas to a heat pump, there's typically no existing electrical circuit at the hot water location at all — meaning new wiring needs to be run from your switchboard to wherever the unit will sit. This is one of the biggest cost variables in a gas-to-heat-pump switch, and it depends heavily on the distance and cable route. If you're replacing an existing electric hot water service, the existing circuit may be reusable, though it still needs assessment against the new unit's requirements and current RCD standards.

Switchboard Capacity Still Needs Checking

Heat pumps draw considerably less power than traditional electric storage systems, so switchboard capacity is less commonly an issue than with other upgrades. However, if your switchboard is older, full, or still running ceramic fuses without safety switches, adding a compliant RCD-protected circuit may require switchboard work regardless of how modest the heat pump's own load is. This should be assessed before installation, not discovered on the day.

Victorian Rebates

Rebates for eligible heat pump and solar hot water products are available through Solar Victoria's programs. Eligibility criteria and rebate amounts change over time, so check the current position on the Solar Victoria website before proceeding. Rebate programs also typically require the installation to be carried out by approved installers meeting specific compliance standards.

Frequently Asked Questions

Do I need a licensed electrician for a heat pump hot water installation?

Yes. Energy Safe Victoria requires wiring, RCD protection, and isolator installation for a hot water service to be carried out by an A-class licensed electrician working under a Registered Electrical Contractor.

Is RCD protection required for heat pump hot water systems?

Yes. Under AS/NZS 3000:2018, RCD protection is mandatory, and a Type A RCD is required for new or upgraded heat pump circuits.

Does a heat pump need a dedicated circuit?

It depends on the manufacturer's specifications, which must be followed under the Wiring Rules. Many units specify a dedicated circuit, so this is confirmed during assessment.

Is switching from gas to a heat pump more electrical work?

Usually yes, since there's typically no existing electrical circuit at the hot water location, meaning new wiring needs to be run from the switchboard.