Solar ROI Guide & Calculator
Estimate solar panel return on investment, payback period, and long-term savings.
What is solar ROI?
Solar ROI is the percentage return on cash you invest after incentives (net cost) versus the utility bills you avoid, summed over a stated horizon—commonly 20 years for comparisons, or full system life for ownership math.
How solar ROI is calculated
Net cost = system price × (1 − tax credit fraction). Each year, bill savings ≈ kWh offset × utility $/kWh, with rates escalating at your assumed annual %. ROI = (cumulative savings − net cost) ÷ net cost × 100 for that horizon. Payback is the year cumulative savings cross net cost.
Key factors
- Electricity rates — Higher $/kWh and faster escalation increase avoided-cost value; always use your tariff class, not a national average, when negotiating.
- Tax credits — Credits reduce net investment; eligibility and basis rules change—model percent of gross cost only if that matches your situation.
- Sun exposure / production — kWh generated (or offset) drives savings. Shade, orientation, and degradation lower effective kWh; this site’s calculator uses your annual usage as offset—tighten production separately with a site estimate.
Solar ROI Calculator · Solar ROI benchmarks · Solar & energy tools (heat pump, EV)