Every payback calculation you see online uses assumptions that may or may not match your house. This guide uses Melbourne-specific assumptions (Victorian feed-in tariffs, typical western suburbs electricity rates, actual network export limits) and runs three scenarios that cover most households we quote: solar only on a new install, solar plus battery on a new install, and adding a battery to an existing solar system.
We'd rather give you an estimated 14-year number than an estimated 5-year sales pitch. If a battery doesn't stack up for your home, we'll tell you.
All rebate amounts, tariffs, prices, savings and payback periods on this page are estimates, not guaranteed outcomes. Substitute your current retailer rates and written quote.
The assumptions behind these numbers
All three scenarios below use an illustrative Melbourne-west household baseline: estimated use of ~20 kWh per day, an estimated ~30c/kWh single-rate import tariff, an estimated ~4.6c/kWh feed-in tariff, and a single-phase connection with a 5kW export limit. Electricity price inflation is assumed at 3% per year, and self-consumption is modelled at 35% without a battery and 75% with one. These are assumptions for comparison—not current guaranteed rates or a quote. Your retailer plan, network approval and household usage will change the result.
Worked example · typical Melbourne-west household · all figures are estimates
Adding a battery to existing solar
Estimated scenario: a Melbourne-west home with estimated 6.6 kW existing solar and an estimated 13.5 kWh battery addition. Every price, rate and result below is an estimate, not a quote or guaranteed saving.
| Step | Estimated calculation |
|---|---|
| Installed price | Estimated installed price: ~$14,500 |
| STC discount | Estimated discount: estimated 13.5 kWh × estimated ~$252/kWh (estimated May–December 2026 rate after admin fees) = ~$3,400 |
| Net battery cost | Estimated ~$14,500 − estimated ~$3,400 = estimated ~$11,100 net |
| Evening energy shifted | Estimated ~10 kWh/day × estimated 300 days = estimated ~3,000 kWh/year |
| Value per kWh shifted | Estimated ~30c import avoided − estimated ~4.6c feed-in forgone = estimated ~25.4c |
| Annual saving | Estimated ~3,000 kWh/year × estimated ~25.4c = estimated ~$760/year |
| Simple payback | Estimated ~$11,100 ÷ estimated ~$760/year = estimated ~14–15 years |
Estimated simple payback for this stated usage case: ~14–15 years. This aligns with an estimated typical Melbourne retrofit payback of 12–15 years; cases with higher evening use, an EV, a VPP or a time-of-use tariff can fall below an estimated 10 years. Your result depends on actual bills, tariff, system and quote.
That’s in line with independent analysis. CHOICE and SolarQuotes estimate around 14 years for an average Melbourne household with an estimated 10 kWh battery. Batteries are estimated to pay back faster in Sydney, Brisbane and Adelaide because electricity costs more there.
What shortens battery payback in Melbourne
Higher evening use. A large family or regular use of ducted heating or cooling at night can increase the amount of stored solar used instead of grid electricity.
EV charging. Charging an EV overnight from the battery or from estimated cheap off-peak rates may improve the value of the system, depending on when and how the vehicle is charged.
Virtual power plants. Joining a VPP may provide payments for battery participation; payments vary by retailer and plan, so check the terms rather than relying on a fixed return.
Time-of-use tariff. A plan with a high evening peak rate can make stored energy more valuable when it offsets electricity purchases during that period.
Earlier installation. The estimated federal STC rate is scheduled to fall from an estimated $272/kWh to an estimated $228/kWh from 1 January 2027, before admin fees. Final eligible discounts depend on the applicable rules and certificate value.
Blackout backup. Backup power has value for households that want essential circuits to keep running during an outage, but a simple payback calculation does not capture that benefit.
The three scenarios
Scenario 1
Solar only, new install (10kW system, no battery)
System cost after STCs: ~$8,500 to $10,000 depending on panel and inverter brand. Annual electricity saving in year one: about $1,500–1,700 (mix of avoided grid purchases and modest feed-in income).
The feed-in tariff contributes less than 15% of the total saving at current rates. The real value is in the power you use yourself during daylight hours and never buy from the grid. Load-shifting your heavy appliances into daytime pushes self-consumption higher and shortens payback without spending a dollar more.
Scenario 2
Solar plus battery, new install (estimated 10 kW solar + estimated 10 to 14 kWh battery)
Estimated combined system cost after STCs and the federal battery rebate: ~$18,000 to $22,000 depending on brands. The estimated battery component adds ~$8,000 to $11,000 net after the Cheaper Home Batteries discount. Estimated annual electricity saving in the first year: ~$2,800 to $3,400, based on the estimated shift in self-consumption from ~35% to ~75%.
The battery's marginal payback (the extra estimated cost of the battery divided by the extra estimated saving it produces versus solar-only) is the number that matters. Estimated battery marginal payback with the rebate is typically 12–15 years for an average Melbourne household; it can fall below an estimated 10 years with higher evening use, an EV, a VPP or a time-of-use tariff.
Scenario 3
Adding a battery to existing solar (retrofit, battery only)
Battery cost and bill savings vary with the equipment, installation and household use. In the worked example above, the estimated net battery cost is ~$11,100 and the estimated annual saving is ~$760 under the stated energy-shift assumptions.
This scenario can make more financial sense when a home exports substantial solar during the day and buys electricity in the evening. Higher evening use, an EV, a VPP or a time-of-use tariff may improve the estimated outcome; homes with little surplus solar to store may see a longer payback.
What moves the needle most
Electricity price rises. Every estimated 10% increase in grid electricity prices shortens both solar and battery payback by roughly an estimated year. This is the single biggest variable you can't control, and it's the main reason payback periods have been shortening even as feed-in tariffs drop.
Self-consumption ratio. The more of your own solar you use (via load-shifting, battery, or both), the more value you extract. A household at an estimated 35% self-consumption gets an estimated half the value of a household at an estimated 75%.
The federal battery rebate. The estimated ~30% discount reduces the upfront battery cost compared with buying without it. The discount is scheduled to shrink from January 2027 onwards.
Your tariff structure. Households on a time-of-use tariff with an estimated high peak rate (35c+) and an estimated low off-peak rate benefit more from a battery than those on a flat rate, because the spread between "free solar" and "expensive peak grid" is wider. If you're seeing low feed-in tariffs and export limits eating into your return, our sun tax and export limits guide explains the mechanics. For a look at which inverter and battery brands we recommend, see the inverter ranking.
Explore the numbers for your home
Estimate a battery size and payback, then ask us to review your home's requirements and prepare a quote.
Common questions
All rebate amounts, tariffs and savings figures in this guide are estimates, not guaranteed outcomes. Payback estimates are modelled on Melbourne western suburbs assumptions as at September 2026, using current Victorian feed-in tariffs, typical residential electricity rates, and the federal Cheaper Home Batteries Program rebate. Actual payback depends on your specific consumption, tariff, roof orientation, shading, and network export rules. Reviewed by Gagandeep Gill before publishing. Confirm personalised numbers at quote stage.