What a home battery does for your bill
A home battery stores the solar your panels generate during the day and lets you use it later, typically in the evening peak, when you would otherwise be buying expensive grid power. In effect it lets you buy less electricity at 30-plus cents a kilowatt-hour and stop exporting cheaply at a low feed-in rate. That gap between your buy rate and your feed-in rate is the core of a battery’s value.
The wider feed-in tariffs fall and the higher retail rates climb, the bigger that gap becomes, which is precisely why batteries have moved from a luxury toward a genuine financial proposition for many solar homes. A battery can also provide backup power during outages if it is configured for it, though not every battery or installation includes that.
How battery payback is calculated
Battery payback works like solar payback: net cost divided by annual saving. The annual saving is mostly the value of the energy you cycle through the battery each day (solar you store and use in the evening instead of importing at peak rates) plus any avoided low-value exports.
The federal Cheaper Home Batteries Program (which started in mid-2025) knocks a substantial chunk off the up-front price, which shortens payback considerably compared with a few years ago. Even so, batteries generally have longer paybacks than solar alone, so the case is strongest where the buy-versus-feed-in gap is wide and the battery is well utilised.
- Take the battery price after the federal battery rebate discount is applied.
- Estimate how many kWh you will realistically cycle through it each day (limited by your surplus solar and your evening usage).
- Value each stored kWh at roughly the difference between your peak usage rate and your feed-in rate.
- Multiply by 365 for the annual saving, then divide net cost by that saving for payback in years.
- Sense-check it against the battery’s warranted life and cycle count. A battery that pays back well inside its warranty period is the goal.
What makes a battery worth it (and what does not)
Batteries reward specific households. You get the strongest return if you have solar generating surplus during the day, meaningful evening and overnight usage, a wide gap between your peak buy rate and your feed-in rate, and a plan or tariff that amplifies that gap (such as time-of-use pricing with a high evening peak).
A battery pays back slowly if your solar is undersized (little surplus to store), your evening usage is tiny (nothing to power from storage), or you oversize the battery well beyond what you can fill and empty each day. An idle battery earns nothing. Utilisation is everything.
The plan behind the battery matters just as much
A battery and an electricity plan work as a system. A time-of-use plan with a high evening peak makes stored solar far more valuable, because every kWh you avoid buying at peak is worth more. Some retailers also offer VPP (Virtual Power Plant) arrangements that pay you to let them draw on your battery at times of grid stress, which can add income but comes with trade-offs around control and cycling.
Because the right plan can materially change whether a battery pays off, it makes sense to model the two together. EnergySorted is independent and values your solar feed-in on every plan, so once you know your usage and export pattern you can see which plan best rewards a battery. Our battery-size calculator helps you avoid the classic mistake of buying more storage than you can actually use.
Beyond the dollars
Not every reason to buy a battery is financial. Backup power during blackouts, energy independence, getting more use out of a solar system you already own, and preparing for an EV or the electrification of your home are all legitimate motivations. Just go in with clear eyes: price the financial return honestly using current rebate and rate figures, and treat backup or independence as a bonus rather than the justification, unless outages are a real problem where you live.