What could solar and a battery save you?

How we work it out

• Usage is your bill divided by the electricity price, after a daily supply charge of about $1.10 a day.
• Solar output is about 3.9 kWh per kW per day in Sydney and 4.2 in south east Queensland, typical yearly averages.
• Suggested solar size covers about 220% of your yearly usage, so there is plenty of daytime energy left to charge a battery and run your home in winter, capped at 26.4 kW. Bigger systems usually need three phase power and network approval. Roof space allows about 5 m² per kW.
• The suggested battery covers about 60% of your average daily usage, so your evening and overnight power comes from your own sunshine. It is rounded to a whole kWh and kept between 10 and 50 kWh.
• Without a battery, about 35% of solar is used at home and the rest exported. A battery soaks up exports to cover more of your evening use.
• Battery rebate follows the Clean Energy Regulator rules: 6.8 STCs per kWh until 31 December 2026 and 5.7 from 1 January 2027. The full factor applies to the first 14 kWh, 60% from 14 to 28 kWh and 15% from 28 to 50 kWh. Nothing above 50 kWh. STCs round down.
• Pricing uses $500 per kW of solar and $500 per kWh of battery as a guide. Your Sungen quote confirms the exact price after a site visit.

This calculator gives a rough estimate only, not a quote or financial advice. Real results depend on your usage pattern, tariff, roof, shading, equipment and eligibility. Sources: Clean Energy Regulator.