Save money on your hot water with a timer
With thanks to the Energy Transition Group and Electrify Boroondara
More and more households in Boroondara and across Victoria are switching to hot water heat pumps – either to replace old gas systems or because they’re one of the most efficient ways to heat water. A heat pump is a great choice, but it can still be one of the biggest contributors to your electricity use (after space heating, EV charging, and pools/spas).
That’s why it makes sense to use a timer.
“Solar Victoria now require hot water heat pumps to have a timer installed in order to qualify for a rebate.”
David Strang, Convenor, Energy Transition Group
Why timing matters
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Hot water heat pumps don’t run continuously – they’re normally programmed to operate for a set period each day (the heating window) until the tank reaches the required temperature.
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Stored heat lasts – modern tanks are well insulated, keeping water hot for at least 24 hours.
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Boosters are available – if you run out of hot water, most units include a booster mode.
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Daytime is more efficient – Hot water heat pumps use less electricity during warmer daylight hours.
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Noise is a factor – if your system is near bedrooms (yours or your neighbours’), avoid running it at night.
When is the best time for your setup?
The right timing depends on your household’s setup – whether you have solar, a battery, and which tariff you’re on.
Here’s a Victorian-specific guide:
Victorian-specific information on heat pump hot water timer settings
Solutions that help the grid
While the recommendations above are designed to reduce your cost, broader benefits of running your heat pump and other equipment across midday hours are:
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Increasing grid load during this period when rooftop solar is generating. This helps the grid to work more effectively as the electricity distribution networks generally have spare capacity during this period.
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Electricity is usually greener during the day due to more wind and solar vs overnight when coal plays a larger role.
Tip for Boroondara households
All Victorian households are experiencing low rooftop solar feed-in tariffs. This makes it much better value to use your solar directly (e.g. for hot water) than to export it.
A local example – the savings add up
Take a Boroondara household with:
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a 5 kW rooftop solar system,
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no battery,
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and a standard Time-of-Use tariff (peak 3–9pm).
If they run their hot water heat pump overnight, the system draws from the grid at ~25–30c/kWh. Running for around 3 kWh/day, that adds up to $270–$330 per year.
If instead they set the timer to run 11am–2pm, the same energy comes directly from their solar, avoiding grid imports. The “cost” is the foregone feed-in tariff (~3–5c/kWh), so the annual cost drops to just $30–$55 per year.
That’s a saving of around $240 per year,
simply by changing the timer.
How to set your timer
Most hot water heat pumps include instructions in the manual, and many manufacturers also provide video tutorials.
For example, the iStore 270L (R290) has clear guides here: iStore LCD setup tutorials.
A couple of quirks to note:
You can’t set start and end times with the same minute (e.g. use 10:01–13:00, not 10:00–13:00).
The iStore tutorials are broken into short clips on different topics, making them easier to follow.
And if you can’t figure it out, don’t struggle alone – ask your installer, your retailer, or local Electrify Boroondara volunteers for help.