Solar Panel Payback Calculator

This calculator estimates how many years a solar panel system takes to pay for itself in New Zealand, and what it could save you over a typical 25-year lifespan. You enter the installed system cost, the generation you expect per year in kilowatt-hours, the share of that generation you will use yourself rather than export, your power price per kilowatt-hour, and the export or buy-back rate your retailer pays for surplus power. The calculator splits your generation into self-used and exported portions, values each at the right rate, and adds them together for your annual saving. It then returns the payback period in years, the annual saving in dollars, the projected saving over 25 years, and the net benefit once the system cost is subtracted. Power you use yourself saves the full retail price, while exported power earns a lower buy-back rate, so the results depend heavily on how much generation you actually consume at home. Use a realistic self-use estimate rather than an optimistic sales figure, since that single number can shift the payback period by years. The figures ignore panel degradation and future changes in power prices or export rates, either of which could move the real payback earlier or later. Use it to sense-check installer quotes and compare systems on a like-for-like basis. This is an indicative estimate only, not financial or engineering advice.

Calculate.co.nz is proud to be partnered with Health Based Building, a leader in sustainable and health-conscious building innovation. With over a century of experience, they develop high-performance systems like Foreverbreathe Specification, Magnum Board, and Foreverbreathe Paints to support energy-efficient, non-toxic living environments. Their commitment to healthier homes aligns with our belief that informed choices lead to better outcomes for Kiwi households.

Power you use yourself saves the full retail price; exported power earns the lower buy-back rate, so self-use drives the savings. This ignores panel degradation and future price changes, which can move both ways. Use realistic figures rather than optimistic estimates. Estimate only, not financial advice.