All states / Massachusetts
Solar in Massachusetts
At 30.49¢ per kWh and 1302 kWh of production per kW each year, a household paying $200 a month needs a 5.68 kW system. Paid in cash, it returns its $15,537 cost in 6.9 yr.
Two prices, two answers
Payback 6.9 yr — at competitive quoted prices ($2.91/W, EnergySage 2026): net cost $15,537, 25-year net $51,059.
Payback 9.2 yr — at typical reported prices ($3.90/W, LBNL 2023): net cost $21,163, 25-year net $45,433.
The gap is methodology, not staleness: the first what you get if you shop around for competitive quotes; the second what the average buyer actually paid, as recorded in permit and incentive data. Every table below uses quoted prices. Why we show both.
By monthly bill
| Your bill | Use / yr | System | Panels | Net cost | Payback | 25-yr net (cash) | Lease, year 1 |
|---|---|---|---|---|---|---|---|
| $100/mo | 3,463 kWh | 2.66 kW | 7 | $6,741 | 6.9 yr | $21,479 | $317 |
| $150/mo | 5,431 kWh | 4.17 kW | 11 | $11,139 | 6.9 yr | $36,269 | $497 |
| $200/mo | 7,399 kWh | 5.68 kW | 15 | $15,537 | 6.9 yr | $51,059 | $677 |
| $300/mo | 11,335 kWh | 8.71 kW | 22 | $24,334 | 6.9 yr | $80,636 | $1,037 |
Cash, loan or lease — at $200 a month
| How you pay | 25-year net | Upfront | Year 1 | Payback / cash flow | Federal credit to you |
|---|---|---|---|---|---|
| Cash | $51,059 | $15,537 | $2,106 | 6.9 yr | $0 |
| Loan $120/mo · 6.99% APR · 20 yr | $37,708 | $0 | $662 | immediate (+$662 in year 1) | $0 |
| Lease / PPA | $18,997 | $0 | $677 | immediate (+$677 in year 1) | $0 |
The 30% federal credit goes to the system owner, not to you. It is reflected in the rate you are offered. The owner claims it at 30% under IRC 48E.
The inputs, and where they came from
| Input | Value | Source |
|---|---|---|
| Residential electricity rate | 30.49¢/kWh | U.S. EIA API v2, electricity/retail-sales, residential sector, 2026-07 |
| Specific yield | 1302 kWh/kW/yr | NLR (formerly NREL) PVWatts v8 API, 1 kW reference system (city:boston-ma) |
| Installed cost | $2.91/W | EnergySage Marketplace real-quote average, as of Sep 2026; page updated 2026-08-28 · LBNL Tracking the Sun 2023 median: $3.9/W, reference only |
| Export compensation | full retail net metering · 100% | 220 CMR 18.04 requires each distribution company to calculate, for a Class I solar net metering facility, a net metering credit equal to 100% of the net excess kilowatt-hours multiplied by the sum of the distribution company charges applicable to the rate class. The Department of Public Utilities raised the threshold for netting without a cap allocation from 10 kW to 25 kW. Follows: All distribution companies (Eversource, National Grid, Unitil) under one regulation. Source, read 2026-09-05. |
| Federal credit, purchase | 0% | IRC 25D (expired) |
| Federal credit, third-party owner | 30% | IRC 48E (Clean Electricity Investment Credit) |
| State incentives | $1,000 | Residential Renewable Energy Income Tax Credit (Schedule EC) (15%, up to $1,000) |
City-level production on file for: Boston. The figures above use Boston.