Solar Calculators for Boston, Massachusetts

Free tools with illustrative Boston planning inputs. Replace energy rates and installation costs with your bill and written quote.

Quick answer

Start with your exact utility account and roof design. The 4.1 sun hours and 24.0 cents/kWh below are planning assumptions, not verified current rates for Boston. Confirm Eversource / National Grid eligibility and export settlement.

Notes updated 2026-07-26

Best for: Boston homeowners comparing a proposal or estimating savings before calling installers.
Inputs needed: 12-month kWh usage, roof shade, Eversource / National Grid, quoted $/W
Formula used: Local production = system kW × local peak sun hours × 365, then adjusted for losses.
Method references: NREL PVWatts, Eversource / National Grid, Massachusetts incentive rules

Peak sun hours

4.1

hrs/day planning assumption

Illustrative energy rate

24.0¢

per kWh (Eversource / National Grid)

Typical install cost

$3.3/W

planning assumption, not a market median

Net metering policy: Full retail net metering ✓

What Boston homeowners should check

Boston combines high electricity prices with compact roofs, winter snow, coastal wind, and frequent shading from nearby buildings. Structural condition, fire setbacks, roof access, and snow-shedding areas can limit the final layout.

Eversource and National Grid serve different parts of the region. Confirm the utility, SMART eligibility, and municipal permit requirements before treating an incentive estimate as guaranteed.

At the state level, Massachusetts currently uses full retail net metering. A typical interconnection takes 6–14 weeks, but utility review and local permitting can extend that range. Check current rules before relying on a proposal's export-credit or installation-date assumptions.

What should I verify before signing a solar contract in Boston?

Confirm that the quote names your actual utility, uses a recent electricity rate, includes measured shade and roof-condition findings, and explains who handles permits and interconnection. Ask the installer to separate guaranteed equipment and workmanship terms from estimated production, incentives, and savings.

Illustrative 8 kW system in Boston

Annual production

10,286 kWh

Retail-value ceiling

$2,469

System cost (est.)

$26,400

Energy-only cost/value ratio

~11 yrs

Illustrative 4.1 peak sun hours, 14.08% production losses, 24.0 cents/kWh and $3.3/W. The retail-value ceiling assumes every kWh earns retail value; lower export credits reduce it. The cost/value ratio is not a full payback model and excludes repairs, financing and rate changes. No new Section 25D homeowner credit in 2026.