The honest answer to "are home batteries worth it?" is: it depends. The economics vary significantly based on your electricity usage, solar system, tariff, and location. Here's a rigorous look at the numbers.
The basic maths
A battery earns its keep by shifting solar energy from when you generate it (daytime) to when you need it (evening). The daily saving is the difference between your import tariff and your feed-in tariff, multiplied by how many kilowatt-hours you shift.
Daily saving = (import rate − feed-in tariff) × daily cycles (kWh)
With a typical import rate of 28–35 c/kWh and a feed-in tariff of 5–8 c/kWh, the saving per kilowatt-hour cycled is roughly 20–28 cents.
A 10 kWh battery cycling fully every day at 25 c/kWh saving = $912/year.
Payback periods in practice
At $10,000–$15,000 installed for a 10 kWh system, and assuming $900–$1,200/year in annual savings, the simple payback is 8–14 years. Most batteries carry a 10-year warranty.
This puts many batteries near break-even over the warranty period — not spectacular, but not terrible either, especially given rising electricity prices and falling battery costs.
The maths improves if:
- Your import tariff is above 30 c/kWh
- Your feed-in tariff is below 6 c/kWh
- You receive a state rebate ($1,500–$3,000 off)
- Electricity prices rise faster than historical averages
- You value backup power capability
Where batteries clearly make sense
High-usage households. If you're using 15–25 kWh/day, a battery can cycle fully every day and the annual saving is proportionately larger.
Time-of-use tariff users. If you're on a tariff with peak rates above 40 c/kWh in the evening, the arbitrage value of a battery is significantly higher.
Households with large solar systems. A 10+ kW solar system generating significant surplus gives a battery plenty to store.
Backup power priority. If you're in a bushfire zone, have a home office, or have medical equipment, the insurance value of battery backup may justify the cost independently of financial ROI.
Where batteries are harder to justify
Low solar export households. If your solar system is undersized relative to your load and you export less than 3 kWh/day, there's not much for a battery to store.
Low tariff differential. In some states and with some retailers, the gap between import and export rates has narrowed. Less gap = less saving.
Small homes with low consumption. A 2-person household using 6 kWh/day has limited ability to cycle a battery meaningfully.
The bottom line
Battery economics are improving year by year as costs fall and feed-in tariffs decline. For many Australian homeowners today, batteries represent a borderline-to-reasonable financial investment — and a good one if you weight backup power and energy independence.
The right way to decide is to run the numbers for your specific situation. Our free calculator takes your usage, tariff, solar system, and location and gives you a complete 25-year financial model.