What Does This Solar Estimator Do?
This estimator takes your electricity bill, home details, and location to estimate the solar panel system that would best suit your household. It provides an estimate of system size in kilowatts, the number of panels required, expected installation costs, yearly energy generation, annual bill savings, and your likely payback period. The results account for factors like roof orientation, shading, your local electricity price, and whether you plan to add battery storage.
How Is the Estimate Calculated?
We start with your electricity consumption—either from your monthly bill or a figure you provide directly. Using average solar irradiance data for your country, adjusted for your roof direction and shading conditions, we calculate how much electricity a solar system would generate annually. Installation costs are based on current average prices per kilowatt in your region. Savings estimates factor in self-consumption rates, export tariffs, panel degradation over 25 years, and projected electricity price increases.
Choosing the Right System Size for Your Home
The ideal solar system size depends on how much electricity you use, not just how big your roof is. A household using 4,000 kWh per year in the UK might need a 4 kW system, while a home using 10,000 kWh in Australia could need 6–8 kW. Oversizing slightly can make sense if you plan to add an electric vehicle or heat pump, but significantly oversizing means more exported electricity at lower rates. This estimator helps you find the balance between covering your consumption and getting the best return on investment.