Solar Savings in Massachusetts — 2026

What the 2026 numbers look like in Massachusetts

The August 2026 EIA residential rate for Massachusetts is 30.48 cents/kWh, 67.8% above the 18.16-cent U.S. average. Installed cost is 2.91 $/W, a verified EnergySage September 2026 state marketplace average; sunlight uses the northeast / mid-atlantic band planning band at 4.3 peak sun hours/day. A measured state installed price exists for Massachusetts, so the cost side of this estimate starts from marketplace data rather than a national proxy. A statewide export-credit rule was verified for this state and is named below.

What actually moves the estimate in Massachusetts

Holding a $150 monthly bill fixed, those inputs size a 4.03 kW array here against 6.06 kW at the national average, produce about 5,315 kWh in year one against 8,921 kWh, and put the interpolated payback at 6.8 years against 16.1 years. The 2.91 $/W price sits +4% relative to the 2.80 $/W benchmark.

That gap is arithmetic from published inputs, not a ranking of states and not an installer quote. Fixed monthly charges, non-bypassable charges, time-of-use periods, annual true-up caps, interconnection limits and a real bid all sit outside this model; the methodology page lists the omissions in full. Replace every default in the calculator below with your own figures.

Example estimates at three bill levels

All three rows hold the same assumptions (90% offset, a south-facing 20-degree unshaded roof, 0.84 derate, no battery, 3% rate escalation, 0.5% degradation, 25 years); only the monthly bill changes. The full default set and every equation are on the methodology page. Replace them in the calculator below with your own figures before treating any row as yours.

At a $150 monthly bill the model sizes a 4.03 kW array producing about 5,315 kWh in year one, needing roughly 222 sq ft of usable roof, with a gross cost of $11,731 and a net cost of $10,731. Year-one savings are $1,620, and the interpolated payback is 6.8 years.

Massachusetts incentive and tariff stack

Massachusetts: 15% state income-tax credit, capped at $1,000. The SMART program pays per kWh produced for a fixed term; it is not included in this model because the rate depends on the capacity block and utility — enter a confirmed value as a utility rebate.

Massachusetts SMART pays per kWh produced for a fixed term; it depends on the capacity block and utility.

Massachusetts: 1:1 retail net metering for residential systems below the size cap; verify the cap and your utility.

Where these numbers come from

• Electricity rate: 30.48 ¢/kWh is the EIA Electric Power Monthly Table 5.6.A August 2026 residential value for Massachusetts, reproduced verbatim. EIA flags 2026 values as preliminary. Table 5.6.B is a year-to-date series and was not mixed in.
• Installed cost: 2.91 $/W — EnergySage state marketplace average, September 2026.
• Solar resource: 4.3 peak sun hours/day, northeast / mid-atlantic band (a planning band, not a station measurement). Use NREL PVWatts for an address-level figure.
• Export regime: Massachusetts: 1:1 retail net metering for residential systems below the size cap; verify the cap and your utility.
• Federal credit: $0. IRC section 25D was terminated for expenditures made after December 31, 2025 under Public Law 119-21.

How Massachusetts compares with the nation and its neighbours

At the U.S. average of 18.16 ¢/kWh and a 2.80 $/W modeling benchmark, the same $150 bill sizes a 6.06 kW array with a $16,972 net cost and a 16.1-year payback. The neighbouring states below show how quickly the inputs change across a border — and why copying a national estimate into a Massachusetts proposal is a mistake.

What to verify first in Massachusetts

• Start with the tariff, not the hardware. At 30.48 cents/kWh, 68% above the national average, a time-of-use plan or a fixed monthly charge can move year-one savings ($1,620) more than a small change in $/W. Ask for 12 months of interval data before anyone sizes the array.
• Price is measured here. The 2.91 $/W figure is an EnergySage September 2026 marketplace average for this state. Compare quotes against it on the same pre-incentive cash basis; financed prices are not comparable.
• Confirm the export rule version. A statewide rule was verified for this state and is described above, but eligibility windows and caps move: check the version that applies to your interconnection date.
• Check the incentive cap and carryforward. A state credit is applied in this model; confirm the statutory cap, whether unused amounts carry forward and whether the program has a waitlist before treating it as cash.

Before you sign in Massachusetts

• Get your utility's export credit in cents per kWh, in writing, and check whether it is locked.
• Compare at least three written quotes on $/W before incentives, with cash and financed prices separated.
• Confirm the Massachusetts incentive stack on DSIRE and your utility program page — caps, carryforwards and waitlists change.
• Ask for a bill-impact analysis built on your 12 months of interval data, not a single annual average.
• If a proposal still shows a 30% federal credit on a 2026 installation, treat every number in it as unverified.