Solar, battery and EV charging calculator

Incentives in 2026

• Solar (STCs): a federal discount taken off the installer's quote, roughly $1,500–2,000 for a 6.6 kW system. It shrinks each year and ends in 2030.
• Batteries (Cheaper Home Batteries Program): about $240–250 per kWh mid-2026 for the first 14 kWh, 60% of that for 14–28 kWh and 15% for 28–50 kWh. It steps down every 6 months to 2030.
• State extras: WA battery rebates and zero-interest loans (with a VPP), a NSW VPP incentive, ACT low-interest loans; SA's funding ran out for most homes in 2026. Most need you to join a VPP.
• Free power (Solar Sharer): from 1 July 2026 in NSW, SE QLD and SA, retailers must offer a plan with at least 3 free hours at midday (up to 24 kWh a day). Other areas are planned from 2027.
• EV chargers: no federal rebate. Check your state and your retailer for any current offers.

The battery "sweet spot"

• The rebate is highest on the first 14 kWh, so for most homes the fastest payback is somewhere around 10–16 kWh. The table in the results works it out for you.
• Go bigger mainly if you use a lot of power at night: an EV charged at home overnight, a pool, or ducted air-con.
• A battery only saves money on the power it actually moves each night. A half-empty battery is money sitting idle.

Rules for installing

• Use an accredited solar and battery installer and products on the approved list, or you can lose the rebates.
• Batteries must follow the Australian standard for where they can go (not in bedrooms, living areas or some escape paths). Your installer should explain the location.
• Your network must approve the system. Many homes are limited to 5 kW of export per phase, and some areas can turn exports down.
• You'll need a smart meter, and for the federal battery rebate the battery must be able to join a VPP (you don't have to join).
• EV chargers must be installed by a licensed electrician. Older switchboards may need an upgrade.

Warranties

• Panels: usually 25 years on output; inverters usually 5–10 years.
• Batteries: usually 10 years, but with limits: a minimum capacity at the end (often 60–70%) and a cap on total energy cycled. Read the conditions.
• A warranty is only as good as the company behind it. Pick brands and installers with a local presence.

Catches and downsides

• Feed-in tariffs are low (often 0–5c), so solar pays best when you use it yourself.
• Free-power plans can charge more outside the window or have a higher supply charge. Compare the whole plan, not just the free hours.
• VPPs let your retailer use your battery. Check how often, how low they can drain it, the payments and the exit terms.
• Upselling. Oversized batteries, "free" batteries with long contracts, and pressure to sign the same day. Get 2–3 written quotes.
• Blackout backup isn't automatic. It usually costs extra and may cover only some circuits.
• Moving house: you rarely get the full value back when you sell.
• Battery replacement: expect to replace a battery once in the life of your panels.
• Rebates step down on a schedule, so prices can rise later, but don't let a deadline rush you into a poor quote.

Other free calculators

For your exact roof, try SunSPOT, and compare plans on Energy Made Easy (Victorian Energy Compare in VIC). Links are below. Driving an EV? See our EV vs petrol cost calculator.

Official sources

• Clean Energy Regulator — Small-scale Renewable Energy Scheme — How the solar and battery discounts (STCs) work, ending in 2030.
• AER — Default Market Offer 2026–27 information kit — Reference prices, usage and the Solar Sharer free windows in NSW, SE QLD and SA.
• SunSPOT (APVI / UNSW) — Free, independent solar and battery estimate using your roof's direction and your own usage data.
• Energy Made Easy (Australian Government) — Compare electricity plans, including Solar Sharer and solar feed-in plans.
• Victorian Energy Compare (Victorian Government) — The plan comparison site for Victoria.
• Green Vehicle Guide (Australian Government) — Energy use per 100 km for your EV.