Solar Panel Payback Calculator
Find out how many years a rooftop system takes to pay for itself, and what it saves across its lifetime once panel degradation and rising power prices are accounted for.
Payback tells you if the maths works
Solar is a long-lived investment, so the question is rarely “does it save money” but “how soon, and how much over its life.” A payback well inside the panel warranty, with strong lifetime savings, is a healthy sign; a payback that approaches the warranty length means the numbers are marginal and worth a closer look at incentives, financing, and your actual rate. Modelling it before you sign keeps a sales estimate honest.
Size the electricity you would offset with the Home Energy Savings Calculator, and see how self-supply changes your carbon footprint.
Frequently Asked Questions
What is solar payback and how is it calculated?
Payback is how long the system takes to earn back its cost through the electricity it offsets. Simple payback divides the net cost — the installed price minus rebates and tax credits — by the first-year bill savings, which is your annual generation times your electricity rate. A $20,000 system with $6,000 in incentives that saves $1,500 a year pays back in about 9.3 years. It is a first approximation; the lifetime figure refines it.
Why do degradation and price inflation matter?
Panels lose a little output each year — typically about 0.5% — so later years generate slightly less than the first. At the same time, grid electricity prices tend to rise, which makes each kWh you self-supply worth more over time. The lifetime savings figure applies both: output fades gently while the value of avoided electricity climbs, then sums the yearly savings across the panel's warranty life and subtracts the net cost.
What generation figure should I use?
Use the annual kWh a reputable installer's proposal estimates for your roof, or a solar production estimate for your location and system size. As a rough guide, each kilowatt of panels produces somewhere between 1,000 and 1,700 kWh a year depending on sun and orientation, so a 6 kW system might make 7,000 to 10,000 kWh. Enter a realistic figure rather than the panels' nameplate rating, which is peak, not annual, output.
Is this financial advice about whether to install solar?
No. It is an educational estimate from the numbers you enter and simple assumptions. Real returns depend on your exact roof, weather, utility rates, net-metering rules, financing, and installation quality, all of which change. Treat the result as a planning aid, and get written quotes and a professional assessment before committing to a purchase or loan.
Estimates only, based on the figures you enter and simple degradation and inflation assumptions. Not financial advice — get written quotes and confirm rates and incentives before deciding.