Massachusetts pays about 30.6¢ per kilowatt-hour for residential electricity and receives about 4.3 kWh per square metre per day of sunlight — 3rd and 38th respectively among the 50 states and DC tracked here. Those two numbers set the ceiling on what rooftop solar returns in Massachusetts, and they point in opposite directions.
Where Massachusetts sits against the rest of the country
Massachusetts is 15.8¢/kWh above the median residential rate across this dataset (14.8¢/kWh) and 0.3 kWh/m²/day below the median insolation (4.6 kWh/m²/day). Under this site's standard assumptions, that combination puts Massachusetts 3rd of 51 for modeled payback speed, at 7.8 years against a dataset median of 13.5 years.
What actually drives payback in Massachusetts
Massachusetts is rate-led: upper half of the dataset for electricity price (3rd), lower half for sunlight (38th). Swap Massachusetts's sunlight for the dataset median and payback moves to 7.4 years (0.5 years of swing). Swap its electricity rate instead and payback moves to 14.8 years (7.0 years of swing). The rate swap is the larger of the two, so what a kilowatt-hour costs is the input deciding the outcome in Massachusetts.
State incentives on record
Recorded for Massachusetts: SMART program incentive payments per kWh (declining block); state personal income tax credit 15% capped at $1,000; property and sales tax exemptions; net metering.
No federal credit is applied above (Section 25D expired 31 December 2025), and export terms often matter more than the headline rate (net metering guide).
The modeled system, in numbers
At Massachusetts's sunlight level a 7 kW array produces roughly 8,569 kWh a year, worth about $2,622 in first-year bill savings at 30.6¢/kWh against an assumed $22,400 installed cost. A ten-year payback at this sunlight level would require a residential rate of about 23.4¢/kWh, which Massachusetts already exceeds.
States with comparable economics
Massachusetts's closest analogues by modeled payback are Connecticut (8.0 years), Rhode Island (8.9 years), Maine (9.6 years). They arrive there from different rate and sunlight combinations, so their incentive rows are the useful comparison.
- Connecticut — modeled payback 8.0 years
- Rhode Island — modeled payback 8.9 years
- Maine — modeled payback 9.6 years
Massachusetts-specific notes
Massachusetts pairs an above-median rate with the SMART per-kWh production incentive and a 15% state tax credit capped at $1,000. Neither is included in the modeled payback above, which is why Massachusetts tends to outperform its modeled rank in practice.