ROI Comparison Tool
Pick your state and a kit to see a personalized 25-year savings projection — including the payback year, annual savings growth as rates rise, and your net profit over the system's lifetime.
Your setup
$0.220/kWh · 4.2h sun · 7.0%/yr escalation
65%
30% (low)100% (battery)
How much of your generation you actually use. Higher if you have a battery or are home during the day. Learn more →
Payback
Year 8
break-even point
Year 1 savings
$37
169 kWh offset
10-year total
$502
cumulative savings
25-year total
$2.2k
$1.9k net profit
Cumulative savings — 25-year projection
savings cost
Based on Maine's $0.220/kWh rate, 4.2h/day sun,7.0%/yr rate escalation, 65% self-consumption, 0.5%/yr panel degradation.
Year-by-year breakdown
| Year | kWh offset | Rate/kWh | Annual savings | Cumulative | vs. cost |
|---|---|---|---|---|---|
| 1 | 169 | $0.220 | $37 | $37 | -$283 |
| 2 | 169 | $0.235 | $40 | $77 | -$243 |
| 3 | 168 | $0.252 | $42 | $119 | -$201 |
| 4 | 167 | $0.270 | $45 | $164 | -$156 |
| 5 | 166 | $0.288 | $48 | $212 | -$108 |
| 6 | 165 | $0.309 | $51 | $263 | -$57 |
| 7 | 164 | $0.330 | $54 | $317 | -$3 |
| 8✓ | 164 | $0.353 | $58 | $375 | +$55 |
| 9 | 163 | $0.378 | $62 | $437 | +$117 |
| 10 | 162 | $0.404 | $65 | $502 | +$182 |
| 11 | 161 | $0.433 | $70 | $572 | +$252 |
| 12 | 160 | $0.463 | $74 | $646 | +$326 |
| 13 | 160 | $0.495 | $79 | $725 | +$405 |
| 14 | 159 | $0.530 | $84 | $809 | +$489 |
| 15 | 158 | $0.567 | $90 | $899 | +$579 |
| 16 | 157 | $0.607 | $95 | $994 | +$674 |
| 17 | 156 | $0.649 | $102 | $1,096 | +$776 |
| 18 | 156 | $0.695 | $108 | $1,204 | +$884 |
| 19 | 155 | $0.744 | $115 | $1,319 | +$999 |
| 20 | 154 | $0.796 | $123 | $1,441 | +$1.1k |
| 21 | 153 | $0.851 | $130 | $1,572 | +$1.3k |
| 22 | 152 | $0.911 | $139 | $1,711 | +$1.4k |
| 23 | 152 | $0.975 | $148 | $1,859 | +$1.5k |
| 24 | 151 | $1.043 | $157 | $2,016 | +$1.7k |
| 25 | 150 | $1.116 | $168 | $2,184 | +$1.9k |
Projections are estimates for planning purposes. Actual savings depend on your usage patterns, local utility rates, and weather. Affiliate disclosure · About self-consumption