Electricity rate as of 2026-06-01. Sun hours: NREL PVWatts, Cambridge fixed tilt annual average; same dataset as Boston (latitude 42.37). Cost per watt: EnergySage 2025-2026, Middlesex County (Cambridge); average 9 kW system approximately $26,300 to $29,160. Payback estimate assumes zero federal residential credit (Section 25D expired December 31, 2025) and current utility net-metering tariffs.

Net metering in Cambridge

Eversource Eastern Massachusetts full retail net metering at approximately $0.2836/kWh (Class I residential, up to 25 kW AC). Credits roll forward monthly at full retail value; annual excess paid at wholesale avoided-cost rate. SMART 3.0 adds $0.03/kWh on all solar production for 20 years (standard income) or $0.06/kWh for income-qualified. In October 2025, Cambridge formally petitioned Massachusetts to lift the Eversource Eastern MA net metering cap, warning it could be reached within three years. Qualified per Eversource Eastern MA tariff as of June 2026.

Available programs

Solar incentives in Cambridge, MA for 2026

Incentives available in MA

Federal residential solar credit (Section 25D): expired. The Section 25D residential investment tax credit expired December 31, 2025. The residential credit rate is 0%. State and local incentives below may still significantly reduce your net system cost. Commercial systems still qualify for Section 48E (30%).

Active solar incentives in MA
Program	Benefit	Eligibility	Status	Source
MA SMART 3.0 Production Incentive Local/State Incentive	$0.03/kWh on all solar production for 20 years (standard income); $0.06/kWh for income-qualified households. SMART 3.0 DPU-approved May 19, 2026. 600 MW AC capacity for Program Year 2026. Verify current Eversource Eastern MA block availability before signing.	Eversource Eastern MA residential customers with new grid-tied solar. Owned systems only.	Active	DSIRE (opens in new tab)
Massachusetts 15% State Income Tax Credit Local/State Incentive	15% of solar system cost as MA state income tax credit, capped at $1,000. Carry-forward up to three years. No set expiration date as of June 2026.	MA residents who own solar on primary residence. Leases and PPAs do not qualify.	Active	DSIRE (opens in new tab)
Massachusetts 20-Year Property Tax Exemption Local/State Incentive	Solar system added value exempt from local property tax assessment for 20 years.	All Massachusetts homeowners with solar.	Active	DSIRE (opens in new tab)
Massachusetts Sales Tax Exemption Local/State Incentive	Solar PV equipment fully exempt from Massachusetts 6.25% sales tax. Saves approximately $1,823 on a typical Cambridge system.	All Massachusetts solar purchases. Automatic.	Active	DSIRE (opens in new tab)
Cambridge Community Electricity (CCE) Standard Green Local/State Incentive	Default supply rate $0.1481/kWh (50% renewable) - below Eversource basic service rate. Economy Green $0.1382/kWh (27% renewable). 100% Green Plus $0.1682/kWh. From 2017 to August 2025, CCE participants saved over $98 million versus Eversource basic service.	All Eversource Cambridge residential accounts enrolled by default since 2017. Opt-out at any time.	Active	DSIRE (opens in new tab)
Cambridge Solar Assistance Program (Resonant Energy) Local/State Incentive	Free consultation, feasibility analysis, and vendor selection support for commercial and large residential property owners. Contact: cambridgesolar@resonant.energy or 617-294-6042.	Commercial and large residential Cambridge property owners with minimum roof area approximately 2,500 sq ft.	Active	DSIRE (opens in new tab)

Data last verified June 29, 2026. Incentive programs change; verify current amounts and availability at dsireusa.org (opens in new tab) before committing to a project.

California property-tax exclusion sunsets December 31, 2026. Solar systems installed and permitted by December 31, 2026 lock in the exclusion for the life of the system under current California law (Revenue and Taxation Code Section 73). Systems installed in 2027 may not qualify if the Legislature does not extend the exemption. Verify current legislative status at ftb.ca.gov before signing a contract.

Why Cambridge homeowners are moving now

After the January 2025 wildfires, battery storage became a priority

In October 2025, Cambridge formally petitioned Massachusetts to lift the Eversource Eastern MA solar net metering cap, warning that at current installation rates the cap would be reached within three years. Homeowners who install before the cap is approached lock in full retail net metering at the current $0.2836/kWh credit rate. Cambridge has legally binding carbon neutrality targets for large non-residential buildings by 2035, creating institutional solar demand that spills over into residential neighborhoods. Harvard's 500 kW rooftop installation at the historic Arsenal on the Charles building, and the joint renewable energy commitment of 11 Boston and Cambridge institutions totaling approximately 1.3 million MWh annually by 2026, demonstrate the scale of university-driven solar momentum in Cambridge.

Source: Cambridge formal petition to lift Eversource Eastern MA net metering cap (October 2025) (2025).

Illustrative example

What does a typical Cambridge solar system actually cost and save?

Zero federal residential credit applied (Section 25D expired December 31, 2025). Figures are estimates based on market data as of 2026-06-29. Your numbers depend on your roof, your utility, and your bill.

System inputs

System size: 9 kW
Gross cost ($3.24/W): $29,160
Federal residential credit: $0 (expired Dec 31, 2025)
MA 15% state income tax credit capped at $1,000: Applied
MA sales tax exemption on equipment: Applied
Cambridge $100 flat PV permit fee: Applied
MA SMART 3.0 $0.03/kWh production payment for 20 years (est. $225/yr on 9 kW): Applied
Estimated net cost: $28,160

Estimated outcomes

Annual savings range: $1,800 to $2,600
Estimated payback: 10.5 years

A 9 kW system at $3.24/W grosses $29,160. Zero federal residential credit applies (Section 25D expired December 31, 2025). Cambridge's $100 flat permit fee is the lowest in Massachusetts. The MA 15% state credit caps at $1,000. SMART 3.0 adds approximately $225/year for 20 years at standard rate. Cambridge's primary constraint is not economics but property access: most of the city is apartments and condos where rooftop solar requires association consent. Single-family homeowners in West Cambridge, Huron Village, Fresh Pond, and Strawberry Hill have the best prospects.

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Neighborhoods we serve

Solar in Cambridge: high-adoption areas, equity zones, and post-fire demand corridors

High-adoption neighborhoods

Established solar saturation; higher installers per block, active neighbor referrals, and permit history at LADBS.

West Cambridge
Huron Village
Fresh Pond
Cambridgeport
Strawberry Hill

Equity program target areas

Designated disadvantaged communities (DAC) eligible for SGIP equity resiliency, DAC-SASH, and other income-qualified programs. Income verification required.

Area IV
East Cambridge
Riverside

Post-fire and growth corridors

Wildfire-affected and adjacent neighborhoods where battery storage demand surged following the January 2025 fires. Rebuilding homeowners and proximate neighbors with elevated grid-resilience priorities.

Alewife industrial conversions
MIT Kendall Square adjacent
North Cambridge

LOCAL INSTALL PHOTO -- CAMBRIDGE -- TO BE PROVIDED

Permitting and interconnection

How solar permitting works in Cambridge

Authority Having Jurisdiction (AHJ)

Permit office: City of Cambridge Inspectional Services Department (ISD)
SolarAPP+ status: SolarAPP+: Not adopted by this AHJ
Permit fee: Cambridge ISD charges a flat $100 per array for photovoltaic permits - the lowest documented solar permit fee in Massachusetts and substantially below Boston's value-based calculation and Worcester's $85-$250 range. Additional electrical service fee: $10 per 100 amps of service capacity if a service upgrade is required. Apply at cambridgema.portal.opengov.com. Contact: isd@cambridgema.gov, 617-349-6100.
Typical contract-to-energization: 7 to 12 weeks (2-4 weeks Cambridge ISD, Eversource interconnection 4-8 weeks)

We handle the permit and interconnection filings

LADBS permit application and plan set preparation
SolarAPP+ submission for qualifying systems
LADWP or SCE interconnection application
Inspection coordination and utility sign-off
Certificate of Completion delivery to homeowner

Cambridge Historical Commission approval is required for work on structures in historic or conservation districts or designated landmarks. Under recent Massachusetts climate legislation, historic commissions must give substantial weight to the threat posed by climate change when reviewing solar applications. Rear-of-roof and non-street-visible installations are most likely to be approved in historic districts. Harvard Square Conservation District and Mid-Cambridge neighborhoods have heightened review. Cambridge's dense multi-family housing limits the share of properties with viable rooftop access.

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Serving Cambridge and surrounding MA communities

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West Cambridge, Cambridge REVIEW -- TO BE PROVIDED

[REVIEW TEXT - TO BE PROVIDED: real customer testimonial from West Cambridge single-family homeowner with details on $100 flat permit fee and SMART 3.0 income]

System: 9 kW rooftop solar, Eversource Eastern MA, SMART 3.0

Fresh Pond, Cambridge REVIEW -- TO BE PROVIDED

[REVIEW TEXT - TO BE PROVIDED: real customer testimonial from Fresh Pond homeowner describing urgency around Eversource Eastern MA net metering cap and Cambridge $100 permit]

System: 7.5 kW rooftop solar, Eversource Eastern MA, net metering cap urgency

Cambridgeport, Cambridge REVIEW -- TO BE PROVIDED

[REVIEW TEXT - TO BE PROVIDED: real customer testimonial from Cambridgeport homeowner with installation experience and bill savings comparison]

System: 8 kW rooftop solar, Eversource Eastern MA

For business owners and property managers

Commercial Solar in Cambridge

Cambridge's institutional and commercial sector (Harvard University, MIT, Kendall Square biotech, Mass General Brigham) is one of the most active commercial solar markets in the region. Harvard's 500 kW rooftop installation at the Arsenal on the Charles demonstrates large-institution feasibility. The federal Section 48E commercial credit (for projects starting construction by July 4, 2026), Eversource Eastern MA commercial net metering, and SMART 3.0 commercial rates apply. Cambridge's legally binding 2035 carbon neutrality target for large buildings creates ongoing institutional demand.

See commercial solar options

Commercial solar projects must begin construction by July 4, 2026 to qualify for the 30 percent Section 48E federal tax credit. After that date, the system must be placed in service by December 31, 2027.

Schedule a Free Commercial Assessment

Cambridge solar questions

What Cambridge homeowners ask

City-specific answers. Every number references your utility and your permit office.

Can I install solar on a Cambridge residential property?

It depends on your property type. Cambridge's dense urban fabric means most properties are apartments, condos, or commercial structures where individual rooftop solar is not feasible without condo association consent and shared-roof agreements. Single-family homeowners in West Cambridge, Huron Village, Fresh Pond, Cambridgeport, and Strawberry Hill have the best prospects for viable rooftop solar. For renters and condo owners, Cambridge Community Electricity and community solar subscriptions are the practical alternatives.

What is Cambridge's solar permit fee?

Cambridge Inspectional Services Department charges a flat $100 per array for photovoltaic permits, the lowest documented solar permit fee in Massachusetts. An additional $10 per 100 amps applies only if a service upgrade is required. The permit fee in Boston is based on project construction value; Worcester's is $85 to $250. Cambridge's flat fee makes it substantially cheaper to permit a solar project than in neighboring communities.

What is the net metering cap risk for Cambridge solar?

In October 2025, Cambridge formally petitioned Massachusetts to lift the Eversource Eastern MA solar net metering cap, warning that at current installation rates the cap would be reached within three years. If the cap is reached before new capacity is approved, new solar installations in Eversource Eastern MA territory - which includes Cambridge - may receive lower compensation rates rather than the current full retail credit of approximately $0.2836/kWh. Homeowners who install before the cap is exhausted lock in full retail net metering.

Is there a federal solar tax credit in 2026?

No. The Section 25D residential federal solar credit expired December 31, 2025. Cambridge and Massachusetts incentives remain active: SMART 3.0 production payments ($0.03 or $0.06/kWh for 20 years), the 15% MA state income tax credit (capped at $1,000), the 20-year property tax exemption, Cambridge's $100 flat permit fee, and the Cambridge Community Electricity below-market supply rate.

More solar resources for Massachusetts:

Massachusetts solar guide All cities

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Cambridge Solar Installation 2026