In Tennessee, a 7.9-kW system for an average home costs about $27,641 after incentives in 2026, saves about $761 in the first year and pays back in more than 25 years.
| Item | Amount |
|---|---|
| Solar, 7.92 kW × $3.49/W | $27,641 |
| Federal credit (0%) | $0 |
| Net cost | $27,641 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $27,641 | $761 | 25+ yr | -$3,681 |
| Rates rise 5.6%/yr (2020–25 pace) | $27,641 | $761 | 22.9 yr | $4,225 |
| Rates stay flat | $27,641 | $761 | 25+ yr | -$9,724 |
| Survey price $3.6/W (LBNL) | $28,512 | $761 | 25+ yr | -$4,552 |
| Add 13.5-kWh battery | $37,361 | $1,225 | 22.7 yr | $5,217 |
| Size to 100% of use instead | $38,390 | $1,056 | 25+ yr | -$5,112 |
Verdict: at average Tennessee numbers, solar is hard to justify on savings alone in 2026 — payback takes more than 25 years, leaving you $3,681 short after 25 years. The main reasons: cheap power (the 8th-lowest price of 51), which caps what each kWh saves; export credits below retail (net billing, exports earn 3¢/kWh), so only the solar you use yourself earns full value. Unless your quote comes in well below the state average or your rate is higher than average, it makes more sense to cut usage first or wait for better export terms.
Net metering and exports in Tennessee: TVA-area utilities have no net metering; TVA Dispersed Power Production pays a few cents per exported kWh.
Battery: a 13.5-kWh battery at the Tennessee average of $720/kWh adds $9,720 and shifts about 4,435 kWh a year from low-paid exports to your own use; payback becomes 22.7 years.
Lease or PPA instead? The owner can still claim the 30% 48E credit if construction began by July 4, 2026 or the system is in service by Dec 31, 2027 — ask whether that discount is in the monthly price.
The full method, material data and tips are on the main solar payback calculator page.