Solar ROI & Energy Calculator
Estimate the system size, upfront cost, payback period, and 25-year savings of a home solar system — every assumption is editable.
Your home energy profile
Adjust the inputs — results update instantly.
about 1,111 kWh / month
Calculation assumptions
Defaults reflect typical U.S. values. Edit them to match your utility and quotes.
Check "price per kWh" on your utility bill
U.S. average is roughly $2.50–$3.50 per watt
Most residential panels are 380–450W
Federal 25D credit expired after 2025; add state or utility incentives
Historical U.S. average is about 2–4% per year
Inverter, wiring, soiling and heat; NREL default is 14%
Also assumed: 25-year lifespan, 0.5% annual panel degradation, savings capped at your own usage (no export credit).
Your solar estimate
Based on your bill, local sunlight, and the assumptions
Recommended system size
8.8kW
22 × 400W panels · ~13,812 kWh / year
Net upfront cost
$24,640
No credits or rebates applied
Payback period
9.1years
When cumulative savings exceed net cost
25-year net savings
$59,749
First-year savings $2,400 · incl. 3% yearly rate increase
Cost breakdown
The 30% federal residential clean energy credit (25D) does not apply to systems installed after Dec 31, 2025. Include any state, local, or utility incentives in the assumptions.
- Gross system cost
- $24,640
- Credits & rebates
- $0
- Your net cost
- $24,640
- 25-yr bill savings
- $84,389
Estimates are for informational purposes only and use simplified assumptions. Fixed utility charges are not offset by solar. Actual costs, incentives, and savings vary by location, utility tariff, roof, and installer.