Solar payback period: how it’s calculated and why quotes disagree
Years until cumulative bill savings equal what you paid. Driven by price per watt, local sunshine, electricity price and export rules.
Payback divides cost by savings, but every input is an assumption: future electricity prices, how exports are credited, degradation, maintenance. Small changes move the answer by years.
Solar Plan Builder shows payback, lifetime net savings and the lifetime cost per kWh of your solar (LCOE) side by side, and lets you change every assumption.
The 30% federal tax credit no longer applies to systems homeowners buy, which lengthens paybacks compared with older articles and calculators.
What this means for you: Compare your solar’s lifetime cost per kWh with your utility’s price. If it’s lower with sensible assumptions, solar is a good deal.