Waltham, MA Solar Panels

Massachusetts homeowners in Waltham who install solar panels on their primary residence can claim a state income tax credit equal to 15% of the net cost of their solar energy system, up to a maximum of $1,000. This credit is applied directly against your Massachusetts state income tax liability, reducing what you owe dollar-for-dollar.

The credit is non-refundable, meaning it cannot reduce your tax bill below zero. However, any unused portion can be carried forward for up to three years, so you won’t lose the benefit if your tax liability is less than $1,000 in the year of installation. To claim it, file Schedule EC with your Massachusetts state income tax return in the year after your system is installed.

Eligibility requires that the system be installed at your principal Massachusetts residence. This is a permanent, ongoing program with no expiration date or funding cap, making it a reliable incentive for homeowners going solar in 2026 and beyond.

Massachusetts exempts all solar photovoltaic equipment — including panels, inverters, racking, and other directly related components — from the state’s 6.25% sales tax. On a $20,000 solar system, this exemption saves you $1,250 right off the top, with no paperwork or application required.

The exemption is automatic and applies at the point of sale. Your solar installer is responsible for not charging sales tax on qualifying equipment, so you do not need to file any forms or seek approval. There is no funding cap and no expiration date on this exemption.

This benefit applies to all Massachusetts residents, including those in Waltham, purchasing a solar system outright or through a loan. Note that if you lease your system or enter a Power Purchase Agreement (PPA), the third-party owner of the equipment receives this benefit, though it may be reflected in your quoted rates.

Under Massachusetts General Laws Chapter 59, §5 (Clause 45), the increased value that a solar energy system adds to your home is completely excluded from your property tax assessment for 20 years from the date of installation. Solar installations can add roughly $4 per watt in home value — meaning a 10 kW system could add ~$40,000 in resale value without a single dollar of additional property tax.

The exemption applies to systems of 25 kW or less, or systems that produce no more than 125% of the property’s annual electricity needs. It is automatic — no application is required — and your local assessor is required by law to exclude the solar system’s value from your assessed valuation during the exemption period.

This is one of the most financially significant long-term benefits of going solar in Massachusetts, as it protects homeowners in Waltham from higher tax bills while still allowing them to enjoy the full increase in home resale value that solar panels provide.

The Solar Massachusetts Renewable Target (SMART) 3.0 program, launched in October 2025 and administered by the Massachusetts Department of Energy Resources (DOER), pays residential solar owners a guaranteed, fixed incentive for every kilowatt-hour (kWh) their system produces over a 10-year contract period. The standard base rate for residential systems (≤25 kW) is approximately $0.03/kWh, with an additional ~$0.03/kWh adder for rooftop installations. Payments are made monthly by your utility — Eversource, National Grid, or Unitil — and are separate from your net metering credits.

Homeowners who pair their solar system with a battery storage unit receive an additional storage adder of approximately $0.04/kWh on top of the base rate, bringing the total to roughly $0.07/kWh. Low-income households qualify for a doubled base rate of $0.06/kWh, and a low-income system paired with storage could earn up to ~$0.10/kWh. For a typical 10 kW system producing ~11,500 kWh/year, the standard rate yields approximately $345/year, or $3,450 over the 10-year term.

SMART 3.0 is available only to customers of the three investor-owned utilities (Eversource, National Grid, and Unitil); municipal light plant customers are not eligible. Program Year 2026 opened January 1, 2026, with 600 MW of available capacity. Applications are submitted through masmartsolar.com, and SMART payments are considered taxable income. Note: DOER is currently issuing Preliminary Statements of Qualification; Final Statements and payment start dates are pending DPU tariff approval.

Under Massachusetts General Laws c. 164, §§138–140 and 220 CMR 18.00, all three investor-owned utilities — Eversource, National Grid, and Unitil — are required to offer net metering to residential solar customers. When your solar panels produce more electricity than your home uses, the excess is exported to the grid and credited to your account at the full retail rate. As of April 2026, the blended retail rate is approximately $0.3151/kWh, with slight variations by utility (approximately $0.28/kWh for Eversource and Unitil, $0.32/kWh for National Grid).

One of the strongest features of Massachusetts net metering is that credits never expire — surplus credits from sunny summer months roll over month to month and year to year indefinitely. Residential systems of 25 kW or less (Class I) automatically qualify and are cap-exempt, meaning there is no waitlist or capacity limit for residential customers. Net metering and SMART are separate programs that can run simultaneously on the same system.

Important regulatory note: In December 2025, the Massachusetts Department of Public Utilities (DPU) opened a formal investigation (docket D.P.U. 25-200) examining electric rate design, including whether to reduce the value of net metering credits. This is an active proceeding and no changes have been adopted as of mid-2026. Homeowners in Waltham should monitor updates from the DPU.

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. Participants receive $275 per kilowatt (kW) of average battery contribution during summer peak events. A typical battery capable of a 5 kW continuous discharge could earn up to $1,375 per year. The program requires a five-year commitment, during which you receive annual payments each summer season.

During the program, your utility may send a signal to your battery up to 60 times per summer (June 1–September 30), between 3:00 p.m. and 8:00 p.m. on non-holidays, with each event lasting a maximum of three hours. You can participate whether you’re installing a new battery with solar, adding a battery to an existing solar system, or installing a standalone battery. Eligible systems include major brands such as the Tesla Powerwall, SolarEdge Home Battery, and Enphase IQ Battery, provided the inverter size is under 50 kW.

As an added benefit, ConnectedSolutions participants qualify for 0% interest financing for their battery storage system through Mass Save. Enrollment must be completed before the summer program season begins (typically June), and your installer can often handle the enrollment process on your behalf. Eligibility is limited to customers of Cape Light Compact, Eversource, and National Grid.

The SMART 3.0 Battery Storage Adder is a bonus incentive available to homeowners who pair their solar PV system with a battery storage unit and enroll in the SMART program through Eversource, National Grid, or Unitil. The adder is approximately $0.04/kWh on top of the standard base rate, bringing a storage-paired residential system to roughly $0.07/kWh total. Over a 10-year contract, this adder can add approximately $4,600–$5,000 in additional payments for a typical 10 kW system.

The storage adder is designed to incentivize battery adoption alongside solar, helping to stabilize the grid by storing excess solar energy for use during peak demand periods. The adder is applied to every kWh your solar system produces — not just the energy stored in the battery — making it a highly valuable addition to the base SMART payment.

To qualify, your battery must be installed and paired with your solar system at the time of SMART enrollment. The adder is available only to customers of the three investor-owned utilities (Eversource, National Grid, Unitil), and the same SMART eligibility rules apply. Low-income households with storage can earn up to ~$0.10/kWh in total SMART payments. Contact the SMART program at [email protected] or 888-989-7752 for application details.

The Residential Clean Energy Credit under Section 25D of the Internal Revenue Code provides a 30% federal income tax credit for battery storage systems installed in your home. Unlike the residential solar ITC (which was eliminated effective December 31, 2025), the battery storage credit remains fully available to homeowners in 2026. On a $10,000 battery installation, this credit is worth $3,000 directly off your federal tax bill.

There is one critical eligibility requirement: the battery must be charged primarily from a renewable energy source — specifically, at least 80% of the energy used to charge the battery must come from solar or another qualifying renewable source. Batteries charged primarily from the grid do not qualify. This makes the credit most straightforward for homeowners who are pairing battery storage with a solar PV system.

The credit is non-refundable, meaning it can reduce your federal tax liability to zero but will not result in a refund for any excess. However, unused credit can be carried forward to future tax years. There is no cap on the system cost or credit amount. Consult a tax professional to confirm your eligibility and ensure proper filing, as this credit is claimed on IRS Form 5695.

National Grid residential customers in Massachusetts can receive a battery storage rebate through the Connected Homes Program. A $2,000 rebate is available for battery installations with a capacity between 5 and 20 kWh, and your battery must be enrolled in the Connected Homes Program before applying for this rebate. Additionally, a $500 rebate is available for battery installations of any size when the application is submitted within six months of installation, appearing as a credit on your utility bill upon approval.

The Connected Homes Program also offers a $100 per kWh rebate for sharing your battery’s capacity through demand response participation. As of 2026, this component of the program is limited to Duracell, Emporia, and Tesla batteries. These rebates can be combined with other incentives such as ConnectedSolutions and the federal Section 25D battery tax credit, maximizing your overall savings.

To apply, submit your application to National Grid within six months of your battery installation. Contact National Grid directly at nationalgridus.com or through your account portal for current program details, eligible equipment lists, and application instructions, as program terms are subject to change.

Through the Mass Save HEAT Loan program, residential customers of participating utilities — including Eversource, National Grid, and Cape Light Compact — can access 0% interest financing of up to $25,000 for qualifying battery storage systems. This no-interest loan makes battery storage significantly more affordable by eliminating financing costs that would otherwise add thousands of dollars to the total investment.

Battery storage systems are explicitly listed as eligible equipment under the HEAT Loan program. Homeowners who enroll their battery in the ConnectedSolutions demand-response program also automatically qualify for this 0% financing, creating a powerful combination: earn annual incentive payments while paying zero interest on your battery loan.

To access the HEAT Loan, work with a Mass Save participating contractor and apply through your utility’s Mass Save program. Loan terms and availability are subject to lender approval. Visit masssave.com or call 1-866-527-7283 to learn more about current financing options and to find a participating contractor in your area.