Waltham, MA Solar Panels

Massachusetts homeowners who install a solar energy system on their primary residence can claim a state income tax credit equal to 15% of the net cost of the system, up to a maximum of $1,000. The credit is calculated on the cost after any upfront rebates have been applied, so it’s important to account for other incentives first. You claim this credit by filing Schedule SC along with your Massachusetts personal income tax return (Form 1), as authorized under Massachusetts General Law c. 62, § 6(d).

If your tax liability in the year of installation is less than the full credit amount, any unused portion can carry forward for up to three years, ensuring you capture the full value of the credit over time. This credit is stackable with other state and federal incentives, making it a straightforward way to reduce the upfront cost of going solar.

Eligibility is limited to systems installed on your primary residence in Massachusetts. Rental properties and secondary homes do not qualify. Be sure to keep all receipts and documentation of your installation costs when filing.

When you purchase solar panels, inverters, and related equipment in Massachusetts, you pay zero state sales tax — a 6.25% exemption authorized under M.G.L. c. 64H, sec. 6(dd). On a typical $20,000 solar installation, this exemption saves you approximately $1,250 right at the point of purchase, with no application or paperwork required on your part.

The exemption applies automatically to qualifying solar energy equipment used in residential solar electric systems. Your solar installer should apply the exemption at the time of sale, so you never pay the tax in the first place. This benefit is available statewide to all Massachusetts residents, including homeowners in Waltham, regardless of which utility serves your home.

This exemption stacks with other Massachusetts incentives such as the state solar tax credit and the property tax exemption, making it one of the simplest and most immediate financial benefits of going solar in the Commonwealth.

Under Massachusetts General Law c. 59, § 5, cl. 45, the increased value that a solar energy system adds to your home is fully exempt from local property taxes for 20 years from the date of installation. This means that even though solar panels can meaningfully increase your home’s market value, your annual property tax bill will not go up as a result — a significant long-term financial benefit.

The exemption is automatic and requires no application from the homeowner. Once your solar system is installed and permitted, the exemption applies by operation of law. This protection lasts for two full decades, covering the majority of a typical solar system’s productive lifespan.

Combined with the sales tax exemption and the state income tax credit, this exemption is part of Massachusetts’ comprehensive approach to removing financial barriers to solar adoption. It is available statewide to all residential solar customers, including those in Waltham, regardless of utility provider.

The SMART 3.0 program, administered by the Massachusetts Department of Energy Resources (DOER) and launched in October 2025, pays residential solar owners a guaranteed, fixed per-kilowatt-hour (kWh) incentive for all electricity their system produces over a 10-year contract period. Payments are made monthly by your utility. The program is open to customers of the three investor-owned utilities — Eversource, National Grid, and Unitil — for systems up to 25 kW. Program Year 2026 opened for applications on January 1, 2026, with 600 MWAC of available capacity.

For solar-only systems, the current base incentive rate has declined to approximately $0/kWh due to rising utility electricity prices, meaning the base rate alone offers limited financial value for new applicants. However, the program becomes significantly more valuable when you pair solar with battery storage: a storage adder of approximately $0.04/kWh is applied on top of the base rate, which can add up to roughly $5,000 over 10 years for an 8 kW solar system with 10 kWh of battery storage. Additional adders include $0.02/kWh for building-mounted systems and approximately $0.06/kWh for qualifying low-income households (roughly double the standard rate).

Applications are processed through the SMART Program Administrator, CLEAResult, via the portal at masmartsolar.com. Municipal light plant (MLP) customers are generally not eligible for SMART but may have access to local MLP rebate programs. Contact the SMART program at [email protected] or 888-989-7752 for eligibility and application assistance.

Massachusetts net metering allows homeowners with solar panels to send excess electricity back to the grid and receive credits on their utility bill at the full retail rate — meaning you are credited for both the supply and delivery portions of your electricity rate. This policy applies to residential systems up to 25 kW (Class I) and is available to customers of the three investor-owned utilities: Eversource, National Grid, and Unitil. Most residential systems at or below 25 kW are cap-exempt and qualify automatically.

One of the most valuable features of Massachusetts net metering is that credits never expire. Surplus generation from sunny summer months rolls over month to month and year to year indefinitely, allowing homeowners in Waltham to bank credits and use them to offset higher electricity bills in winter. This effectively allows a properly sized solar system to offset close to 100% of a household’s annual electricity costs.

As of March 2026, the 1:1 retail credit structure and 25 kW residential cap remain in effect with no significant changes pending. If you are a customer of a municipal light plant (MLP), net metering policies may differ — check directly with your MLP for details. For regulated utility customers, the official net metering guide is available at mass.gov.

Community solar — also called virtual net metering — is an alternative for Massachusetts residents who cannot install rooftop solar, such as renters, condo owners, or those with shaded or structurally unsuitable roofs. Subscribers sign up for a share of a local solar farm and receive credits directly on their utility bill for their portion of the farm’s electricity production, typically saving 5%–10% on electricity costs with no upfront investment or installation required.

Under Massachusetts’ SMART 3.0 program, all Community Shared Solar (CSS) projects must enroll a minimum of 40% low-income customers. Market-rate subscribers are guaranteed a minimum 10% discount off their electricity bill, while qualifying low-income subscribers receive a minimum guaranteed 20% discount, making community solar one of the most accessible clean energy options in the state.

Community solar is available to customers of Eversource, National Grid, and Unitil. Subscriptions are typically offered through third-party community solar developers. There is no long-term equipment commitment, and many programs allow you to cancel with reasonable notice. Check the Massachusetts Clean Energy Center’s Energy Savings Finder at goclean.masscec.com for available projects in your area.

The ConnectedSolutions program, administered through Mass Save in partnership with Eversource, National Grid, and Cape Light Compact, pays homeowners annual cash incentives for enrolling their home battery storage system in a demand-response program. During summer peak demand events, the utility draws power from your battery to help stabilize the grid, and you are compensated at a rate of approximately $275 per kilowatt (kW) of average contribution. For a typical battery system capable of a 5 kW continuous discharge, this can amount to up to $1,375 per year. Most homeowners with a single Tesla Powerwall earn $500–$750 annually, while those with two Powerwalls can earn $1,000–$1,500 per year.

The program typically requires a five-year commitment, during which you receive annual payments for participation during summer (and in some cases winter) peak seasons. Eligible battery systems include major brands such as the Tesla Powerwall, SolarEdge Home Battery, and Enphase IQ Battery, provided the inverter size is less than 50 kW. You can enroll a new battery installed alongside solar, add a battery to an existing solar system, or install a standalone battery — all are eligible.

To participate, you must be a customer of Cape Light Compact, Eversource, or National Grid. Mass Save also offers 0% interest HEAT Loans of up to $25,000 to help finance battery storage installations, making it easier to get started with little or no upfront cost. Visit masssave.com or call your utility to enroll.

The federal Residential Clean Energy Credit (Section 25D) provides homeowners with a 30% tax credit for the cost of installing a battery storage system, as long as the battery is charged primarily from a renewable energy source. Specifically, at least 80% of the energy stored in the battery must come from solar panels or another qualifying renewable source — batteries charged primarily from the grid do not qualify. This credit is applied dollar-for-dollar against your federal income tax liability and is claimed on IRS Form 5695.

The 30% credit rate is in effect through 2032, after which it is scheduled to step down. For a $10,000 battery installation, the credit is worth $3,000. Importantly, unlike the residential solar ITC (which expired at the end of 2025), this battery storage credit remains fully available to homeowners in 2026, making it one of the most valuable federal incentives currently on the table for residents of Waltham pairing solar with storage.

This credit can be combined with Massachusetts state incentives such as the ConnectedSolutions program, the SMART 3.0 battery storage adder, and the NextZero Battery Program (for municipal utility customers), creating a powerful stack of incentives for battery storage installations. Consult a tax professional to confirm your eligibility and ensure the credit is properly claimed on your return.

The NextZero Battery Program, administered by the Massachusetts Municipal Wholesale Electric Company (MMWEC), provides a rebate of $100 per kWh of rated battery storage capacity for residential customers of participating municipal light plants (MLPs). For example, a battery with a 15 kWh rated storage capacity would receive a $1,500 rebate. This program is specifically designed for MLP customers, who are generally not eligible for the investor-owned utility programs like ConnectedSolutions or SMART.

As of 2026, eligible battery brands under the NextZero program are limited to Duracell, Emporia, and Tesla. Homeowners should confirm their municipality participates in the program and verify the current list of eligible battery models before purchasing, as the approved brand list may be updated over time.

The NextZero Battery Program can be combined with the federal Residential Clean Energy Tax Credit (30% for battery storage) and the Massachusetts Solar Tax Credit if the battery is installed alongside a solar system, providing MLP customers with a meaningful incentive stack even without access to SMART or ConnectedSolutions. Contact your local municipal utility or MMWEC directly to confirm participation and application requirements.

The SMART 3.0 Battery Storage Adder is a bonus incentive available to homeowners who pair their solar system with a battery storage unit and enroll in the SMART program through Eversource, National Grid, or Unitil. The adder adds approximately $0.04 per kWh on top of the base SMART incentive rate for every kilowatt-hour the solar system produces over the 10-year contract period. For an 8 kW solar system paired with 10 kWh of battery storage, this adder can be worth approximately $5,000 over the full 10-year term.

This adder is particularly important in 2026 because the base SMART rate for solar-only systems has declined to approximately $0/kWh due to rising utility electricity prices. The battery storage adder effectively makes the SMART program financially meaningful again for new residential applicants — but only for those who include battery storage in their installation. Additional adders are also available: $0.02/kWh for building-mounted systems and approximately $0.06/kWh for qualifying low-income households.

To access the battery storage adder, your system must be enrolled in the SMART program through the official application portal at masmartsolar.com, administered by CLEAResult. The battery must meet program specifications, and the system must be interconnected with the grid. Contact the SMART program administrator at [email protected] or 888-989-7752 for details on qualifying battery systems and application requirements.