Can I run my hot water off solar in Perth?

Last updated: 22 October 2026

The short answer

Yes. Hot water is one of the biggest loads in a home, and a heat pump on a timer heats the tank in the middle of the day from solar you would otherwise export for as little as 2c/kWh. That makes it a system decision as much as an appliance one: it belongs in the same conversation as your panel and battery size.

Why is hot water a good load to move onto solar?

Water heating is around 23% of the energy an average Australian home uses, and its largest single source of emissions. A heat pump moves heat from the air rather than making it, so it uses about a third of the electricity of a standard electric storage tank. Run on solar, it is close to emissions-free.

Those are national figures. We have no WA-specific running-cost model to quote, so the saving for your home depends on your tariff and how much of the heating lands in solar hours.

Can I run my hot water system off my solar panels?

Yes, and it is one of the most useful jobs for daytime solar. Set the heat pump's timer to the sunniest hours, roughly 10am to 2pm, and it soaks up surplus generation instead of sending it to the grid. On Synergy's Midday Saver plan those hours also fall inside the cheapest window for grid power.

A battery is not needed for this. The tank itself stores the heat, so the battery stays free for the evening.

Is there a rebate for heat-pump hot water in WA?

The incentive is federal. Air-source heat pumps earn small-scale technology certificates (STCs), which can come off the price upfront. We found no WA state rebate for heat-pump hot water in the sources we track. The WA battery rebate covers batteries only, so it does not extend to hot water.

The number of certificates depends on the model, so ask for the STC discount as its own line on the quote. That shows the real price after the discount.

Should I replace gas hot water with a heat pump?

If you are cutting gas and making your own solar, a heat pump is usually the better swap: it uses about a third of the electricity of a plain electric tank, leaving more of your solar for the house and battery. If hot water is your last gas appliance, disconnecting gas also ends the daily gas supply charge.

Our suggested pick

For a Perth home going solar-first: a heat pump on a midday timer, sized with the rest of the system so the panels cover it.

What should I check before choosing a heat pump?

Check its efficiency, the warranty, whether it suits the space it will sit in (noise and airflow), the STC discount on that model, and who services it in WA. It must be installed to the Australian plumbing standard for heated water, with the tank kept hot enough to prevent Legionella and a tempering valve on the outlet.

We don't rank brands. Ask the installer for two models priced after the STC discount and compare them on those points.

Does a heat pump change the solar size I need?

It can. A heat pump adds a daily load that runs in solar hours, so a home planning one may suit the next panel size up. Tell the installer it is coming, even if it is a year away, so the array is sized for it now rather than topped up later at a second installation cost.

The solar and battery sizing guide explains how planned loads feed into the size.

Plan the hot water into your system

Tell us about your home and an installer from our network that covers your area gives you a free, no-obligation quote. Mention the hot water in your notes.

Get a free solar and battery quote

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