You’ve Got a Battery. But What’s Still Draining It?
When the federal government launched the Cheaper Home Batteries Program on 1 July 2025, homeowners jumped on it. In just a few weeks, over 11,500 batteries were installed across Australia. That’s more than 1,000 installs a day, and momentum is only building.
It’s a smart move, but most people are making the same critical mistake we flagged in our original post:
How the New Battery Rebate and Smart Plumbing Work Together to Slash Your Power Bills
They’re installing batteries without upgrading the biggest energy drain in the house — the hot water system.
The Silent Killer in Your Energy Setup
If you’ve got a 10–13 kWh battery – Most standard electric hot water systems draw 3.6 to 4.8 kW per heating cycle. If you’re running a 10 to 13 kWh battery, like those from Tesla, Sonnen, or Sungrow, that means just one recharge cycle from your hot water system can use 30 to 50 percent of your total stored energy.
For example:
A 180L electric storage system may run for 2–3 hours overnight to maintain temperature, drawing a steady 3.6 kW. That’s 10.8 kWh — nearly the full charge of a standard home battery.
So even if the draw is spread over the night, the total energy use often equals a third to half of your battery’s capacity — gone before you even boil the kettle in the morning.
The Smarter Move: Heat Pump + Battery
In our previous article, we explained why pairing your home battery with a smarter hot water system isn’t just a good idea — it’s essential. Since then, demand has surged across Australia, and the need to integrate your energy systems has only grown stronger.
Heat pump hot water systems are at the heart of this smarter setup. They:
- Use ambient air to heat water, reducing electricity consumption by up to 70 percent
- Can be programmed to run during the day, when your solar is producing or your battery is fully charged
- Are fully electric and future-ready, bypassing the looming gas phase-outs already legislated in Victoria and Sydney
- Qualify for additional state-based rebates that can be combined with the federal battery rebate
It’s not just homeowners making this shift. Governments are rolling out heat pumps and batteries in new public and community housing projects because the data is clear — it cuts bills, slashes emissions, and builds more resilient housing stock.
If you’re building or upgrading in Queensland, it’s even more relevant. From January 2025, new energy efficiency standards will push homes toward all-electric setups, making heat pumps and battery storage the default rather than the upgrade. We’ve broken that down in more detail in this article:
Building a Home in 2025: What Queensland’s New Energy Rules Mean for You
What’s Happening Now
- Federal battery rebates are live, but installer availability and equipment stock are tightening fast
- Most households still haven’t addressed their old hot water systems
- The opportunity to stack rebates for batteries and heat pumps is real, but won’t last forever
- This is the moment to build a full energy strategy, not just tick the battery box
Why Acting Now Matters
The longer you wait, the less value you’re likely to get. As the rebate phases down and installer queues grow, those who delay could miss out entirely or pay more for rushed, incomplete installs.
If you’ve already installed a battery — or are about to — now’s the time to assess what else is drawing on that power and whether your hot water system is helping or hurting.
What RJT Plumbing & Gas Can Do for You
We’re not just swapping units. We’re helping people design smarter home energy systems that work as a whole.
- Assess your existing hot water setup
- Recommend and install a heat pump system matched to your battery and solar profile
- Coordinate with your existing installer to ensure everything integrates cleanly
- Help you access any available rebates
- Future-proof your home for incoming electrification standards
Final Word
We said it before, and it’s even more urgent now:
A battery by itself won’t save you money if your hot water system is still doing things the old way.
Click here to read our original breakdown of the battery rebate and plumbing connection:
How the New Battery Rebate and Smart Plumbing Work Together to Slash Your Power Bills
And if you’re ready to take the next step, get in touch with the team at RJT Plumbing & Gas. We’ll help you build a system that’s smarter, cleaner, and more efficient from the ground up.
