Most "solar calculators" online give you a single payback number with no working underneath. Coming from project finance — where solar is literally modelled as a 25-year asset with IRR, refinancing, and battery degradation — that always felt absurd to me. RoofSolar runs the same DCF logic, just pointed at your home: enter your address and you get a 25-year cashflow, IRR, payback period, export-tariff earnings, battery economics, and EV-charging savings. Live PVGIS irradiance data, no signup, worldwide coverage. The Pro PDF (€3.99 one-off) gives you something you can hand to your installer or accountant — actual numbers under each assumption, not just a glossy quote. Built this because I kept seeing friends sign 20-year solar loans on the back of a one-line "you'll save €X/month" promise. You deserve to see the cashflow. Free analysis is the whole core product. Pro just unlocks the PDF export. Would love your feedback — especially which country's tariff rules you want me to refine next.

RoofSolar

Financial-grade solar analysis for your roof — in 3 minutes

Financial-grade solar analysis for your roof — in 3 minutes