In Delaware, a 8.8-kW system for an average home costs about $17,144 after incentives in 2026, saves about $1,985 in the first year and pays back in 7.8 years.
| Item | Amount |
|---|---|
| Solar, 8.8 kW × $2.63/W | $23,144 |
| Federal credit (0%) | $0 |
| State incentive | −$6,000 |
| Net cost | $17,144 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $17,144 | $1,985 | 7.8 yr | $53,395 |
| Rates rise 5.6%/yr (2020–25 pace) | $17,144 | $1,985 | 7.2 yr | $82,108 |
| Rates stay flat | $17,144 | $1,985 | 8.6 yr | $31,460 |
| Survey price $3.6/W (LBNL) | $25,680 | $1,985 | 11.1 yr | $44,859 |
| Add 13.5-kWh battery | $32,710 | $1,985 | 13.6 yr | $37,829 |
| Exports cut to 50% of retail | $11,889 | $1,023 | 10.3 yr | $22,974 |
Verdict: at average Delaware numbers, solar is a strong investment in 2026 — payback takes 7.8 years, leaving you $53,395 ahead after 25 years. The main reasons: 1:1 net metering, which credits every exported kWh at the full retail price; a state incentive worth about $6,000. 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 Delaware: Net metering (<=25 kW) in kWh credits.
Battery: a 13.5-kWh battery at the Delaware average of $1,153/kWh adds $15,566 and saves almost nothing extra under 1:1 net metering — buy it for backup, not payback; payback becomes 13.6 years.
EnergySage's Delaware page lists a 13.1-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.