Solar FAQ

Our calculator uses Bureau of Meteorology sunshine data, current electricity rates, and realistic assumptions for panel wear (they lose about 0.5% output per year), inverter replacement (around year 12), and battery degradation. While no calculator can predict exact future returns, we capture the key factors that affect your solar savings.

For most Australian households, a 6.6kW system is the sweet spot — it's the largest size that gets the full federal rebate while covering typical usage. Larger homes with pools, electric vehicles, or ducted air conditioning may benefit from 8-10kW systems. Our calculator recommends a size based on your roof space and usage.

It depends on your electricity plan. If you're charged more for power during peak hours (usually 4-9pm), a battery can save you $15,000-20,000 over 25 years by storing your free solar power for those expensive hours. If you're on a flat rate, batteries often struggle to pay for themselves.

Most Australian households see payback in 4-7 years for solar-only systems. South Australia and Victoria tend to be faster due to higher electricity prices. Adding a battery extends payback to 7-11 years but can improve your total savings over 25 years if you're on time-of-use pricing.

The federal government provides an upfront discount of $2,500-3,500 for a typical system through Small-scale Technology Certificates (STCs). Your installer handles this — you just see a lower price. Some states offer additional rebates: SA and WA have battery schemes, Victoria has Solar Homes (means-tested), and NT offers up to $6,000 for batteries.

Location is biggest — Queensland generates 30% more than Tasmania. Roof direction matters (north-facing is ideal), as does shading from trees or buildings. Panels also lose a tiny bit of output each year (about 0.5%), and perform slightly worse in extreme heat.

Battery prices are falling 5-10% per year, but electricity prices are rising too. A reasonable strategy: install solar now and add a battery in 2-3 years. By then you'll have real data on your usage patterns and can right-size the battery.

Instead of paying the same rate all day, you pay different amounts depending on when you use power. Typically: cheap overnight (15-20c), moderate during the day (25-30c), and expensive during peak hours 4-9pm (45-55c). This makes batteries much more valuable — you avoid buying expensive peak power.

South Australia has the best economics — highest electricity prices in Australia. Queensland and Western Australia have the best sunshine. Victoria and NSW have strong returns due to high prices despite moderate sunshine. Tasmania has the longest payback due to less sunshine.

Quality panels last 25-30 years, with most manufacturers guaranteeing at least 80% of original output after 25 years. Inverters typically last 10-15 years and will need one replacement. Our calculator includes this cost.