The solar payback period is the time it takes for your electricity-bill savings and solar export income to recover the system’s upfront cost. A basic estimate divides the net purchase cost by expected annual savings, but results depend on system size, electricity use, feed-in tariff, energy prices, roof position, shading and whether a battery is included. Ask several accredited installers for itemised quotes and realistic production estimates, then compare them with recent bills rather than relying on advertised figures. Your actual payback period will depend on your circumstances and future energy prices.