In Maine, a 5.3-kW system for an average home costs about $15,418 after incentives in 2026, saves about $1,934 in the first year and pays back in 7.3 years.
| Item | Amount |
|---|---|
| Solar, 5.28 kW × $2.92/W | $15,418 |
| Federal credit (0%) | $0 |
| Net cost | $15,418 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $15,418 | $1,934 | 7.3 yr | $54,518 |
| Rates rise 5.6%/yr (2020–25 pace) | $15,418 | $1,934 | 6.8 yr | $83,221 |
| Rates stay flat | $15,418 | $1,934 | 8 yr | $32,628 |
| Survey price $3.6/W (LBNL) | $19,008 | $1,934 | 8.7 yr | $50,928 |
| Add 13.5-kWh battery | $31,226 | $1,934 | 13.4 yr | $38,710 |
| Exports cut to 50% of retail | $10,278 | $981 | 9.4 yr | $23,165 |
Verdict: at average Maine numbers, solar is a strong investment in 2026 — payback takes 7.3 years, leaving you $54,518 ahead after 25 years. The main reasons: electricity that costs more than in all but 2 states; 1:1 net metering, which credits every exported kWh at the full retail price. Pay cash if you can: Berkeley Lab found loan-financed systems priced about $1.50/W above cash installs in 2025, which can add years to the payback.
Net metering and exports in Maine: Net energy billing in kWh credits with 12-month expiration.
Battery: a 13.5-kWh battery at the Maine average of $1,171/kWh adds $15,809 and saves almost nothing extra under 1:1 net metering — buy it for backup, not payback; payback becomes 13.4 years.
EnergySage's Maine page lists a 11.3-year payback. Its method is not fully published; ours uses EIA's Jan–Aug 2026 price, 1:1 net metering, 3%/yr rate growth and 0.5%/yr panel aging, with no federal credit.
The full method, material data and tips are on the main solar payback calculator page.