The short answer
A battery is worth it when your solar sends a lot of power to the grid during the day and your household uses a lot after dark. It is a harder case if you use most of your power while the sun is up, or if your solar system is small.
Most Melbourne homes sit somewhere in between, so it pays to check with your own numbers rather than a rule of thumb.
How a battery saves you money
Without a battery, any solar you do not use straight away is exported to the grid. Feed-in tariffs in Victoria have fallen to a few cents per kWh or less, while power bought back in the evening often costs 25 to 35 cents per kWh or more.
A battery stores that midday surplus and releases it in the evening. Every kWh you shift is worth roughly the difference between what you would pay to buy it and what you would be paid to export it.
Work it out from your own bills
You need three numbers, all on your bill or in your retailer’s app:
- How much you export: the average kWh per day sent to the grid.
- How much you buy after dark: if your bill splits peak and off-peak, or your app shows hourly use, add up the evening and overnight kWh.
- Your rates: the usage rate you pay and the feed-in tariff you receive.
The power you can shift each day is the smallest of three things: what you export, what you buy after dark, and the battery’s usable capacity. Multiply that by the difference between your two rates, then by 365.
Example: a household exports 14 kWh a day and buys 11 kWh after dark. With a 13.5 kWh battery it can shift about 11 kWh a day. At 30c to buy and 3c to export, that is 11 × 27c ≈ $2.97 a day, or roughly $1,080 a year. Winter solar is weaker, so the real figure will be lower; we model it month by month.
Divide the installed price, after the rebate, by the yearly saving for a rough payback period, then compare it with the battery’s warranty, which is usually 10 years.
The rebate changes the maths
Since July 2025 the federal Cheaper Home Batteries Program has cut the upfront cost of eligible batteries, applied as a discount on your quote. The discount depends on the battery’s usable capacity and steps down each year until the program ends in 2030. Our guide to solar and battery rebates in Victoria explains how it works.
Value that does not show on the bill
- Backup power: a battery set up for backup keeps the lights, fridge and internet on during an outage, which matters in storm-prone areas like the outer east and the Dandenongs.
- Virtual power plants: some retailers pay you to let them draw on your battery at peak times. Read the terms closely before signing up.
- Less exposure to price rises: the more of your own power you use, the less future tariff increases affect you.
When we would tell you to wait
- Your solar system is small (under about 5 kW) and rarely exports much.
- The house is empty most evenings, or you already use most of your power during the day.
- Your switchboard or solar inverter needs replacing first. Sort that, then add storage.
What size battery do you need?
Size the battery to what you use after dark, not to the biggest model on offer. Many Melbourne homes do well with 10 to 15 kWh. Larger batteries make sense with high evening use, electric heating, or an EV that charges overnight.
How we work it out for you
Almost every Victorian home has a smart meter, so you can download twelve months of half-hourly data from your electricity distributor’s online portal. Send it to us with a recent bill and we will model your savings month by month before recommending anything. If a battery does not stack up for your household yet, we will say so.
Learn more about our home battery installation service, or request a free assessment.