Would a home battery actually save you money?
Use a transparent calculator to estimate STCs, net battery cost, annual bill savings and simple payback before you start comparing installer quotes.
No signup required for the calculator. No installer partnership is implied.
New to home batteries? Start here.
You do not need to understand kilowatt-hours, STCs or inverter jargon before using the calculator. These short explainers cover the basics first.
01 What is a home battery? +
A home battery stores electricity so you can use it later. In most Australian homes with rooftop solar, the battery charges during the day when your panels are producing more electricity than the house is using.
Instead of exporting all that spare solar to the grid, some of it is stored in the battery. Later, when the sun goes down, the home can use the stored energy before buying electricity from the grid.
02 Do I actually need one? +
Not everyone needs a battery. They tend to make more sense when you already have solar, export a decent amount of solar during the day, and then buy expensive electricity from the grid in the evening or overnight.
A battery may be less compelling if you use most of your solar during the day already, have very low electricity use, or the battery price is high relative to the savings you are likely to make.
03 Do I need solar first? +
For the current federal Cheaper Home Batteries Program, the battery needs to be connected to new or existing rooftop solar. In practical terms, solar is also what gives most households the low-cost daytime energy they want to store.
If you do not already have solar, it can still make sense to look at a combined solar-and-battery system rather than treating the battery as a completely separate purchase.
04 What does a battery actually save me? +
The main saving comes from using your own stored solar later instead of buying electricity from the grid.
For example, if you would otherwise export solar for 6 cents per kWh and later buy electricity for 38 cents per kWh, storing and reusing that energy can be much more valuable than exporting it. Real savings still depend on battery efficiency, tariffs, household use and the installed price.
05 What size battery do I need? +
A useful first step is to compare two things: how much solar you export during the day, and how much electricity you use after the sun goes down.
If you only have 6 kWh of spare solar available most days, buying a 20 kWh battery purely for daily bill savings may not make sense. Bigger is not automatically better.
Read the simple sizing guide →06 Will it keep my house running in a blackout? +
Sometimes, but not automatically. Backup capability depends on the battery, inverter, installation design and whether backup hardware has been included.
If blackout protection matters to you, ask the installer exactly which circuits will stay powered, how much reserve will be kept in the battery, and what happens during a prolonged outage.
A big purchase deserves a clearer answer.
Battery economics are driven by what you export, what you buy from the grid, your tariffs, battery capacity, installed price and the value of eligible STCs.
Estimate support
See an indicative STC count using the official factor table and 2026 capacity taper.
Learn how it works →Estimate savings
Use your daily grid use, solar exports and tariffs instead of relying on a generic sales claim.
Use the calculator →Right-size the battery
Compare your evening demand with available solar exports before assuming bigger is better.
Read the sizing guide →What changed on 1 May 2026?
The STC factor for batteries installed from May to December 2026 is 6.8 per kWh before the size taper. Support is applied at 100% of the factor for the first 14 kWh, 60% for capacity above 14 to 28 kWh, and 15% for capacity above 28 to 50 kWh.
Eligible battery systems can be up to 100 kWh, while STCs are calculated on the first 50 kWh of usable capacity. The program aims to maintain support of around 30% across a range of battery sizes, but the actual customer discount depends on STC entitlement and how the certificates are valued or assigned.
Read the rebate guideThree useful checks.
Check your bill
Find average daily grid usage, solar exports, import tariff and feed-in tariff. These make the estimate far more useful.
Check accreditation
Official guidance says to use an SAA-accredited installer and a CEC-accredited battery product.
Compare more than one quote
Government guidance recommends seeking multiple retailer or installer quotes and checking the value of the discount, warranty and anticipated payback.
The important bits.
Is Battery Simple an official government site?
No. It is an independent planning site. Official eligibility and STC entitlements should always be confirmed with government sources and your installer or retailer.
Does a battery always pay for itself?
No. Savings depend on the installed cost, battery size, solar exports, household use, import tariffs, feed-in tariffs and how the system is operated.
Can I get quotes here?
The launch version collects quote-matching interest only. Installer details will not be shared until real partners are in place and you have explicitly consented.