Solar Roof Calculator

Panel Count, System kW & 25-Year Savings

The Solar Roof Calculator returns the number of solar panels, system size in kW, total install cost, payback period, and 25-year savings for your home. Enter your monthly electric bill, average daily sun hours for your region (3-6 in most US zones), and panel wattage (typical 400W) and the tool sizes the system. Federal tax credit (30%) and net metering can dramatically improve payback. Pair with our Roof Area and Insulation calculators when planning a full energy retrofit.