Net Metering in Massachusetts: How It Works and What Homeowners Should Know

If you've been looking into solar in Massachusetts, you've probably noticed that the financial case looks compelling — even without the federal tax credit, which expired at the end of 2025. A big reason for that is net metering. It's one of the most important pieces of the solar savings picture, and Massachusetts has historically offered one of the strongest versions in the country.

Here's a clear breakdown of what net metering is, how it works specifically in Massachusetts, and what the current regulatory picture means for homeowners thinking about going solar right now.

What Is Net Metering?

Net metering is a billing policy between you and your utility. When your solar panels produce more electricity than your home is using at a given moment, that surplus flows back to the grid. Net metering determines what you get in return for it.

Under a full retail-rate net metering program — which Massachusetts currently has — you receive a bill credit for exported electricity at the same rate you'd pay to purchase it. In 2026, that means approximately $0.28/kWh for Eversource customers, $0.32/kWh for National Grid, and $0.28/kWh for Unitil. Those are among the highest credit rates in the country.

Without net metering, utilities would pay a wholesale rate for your excess power — often just 3–5 cents per kWh — while still charging you full retail when you draw from the grid. The difference between those two scenarios has a dramatic effect on whether solar pencils out financially.

How Net Metering Works in Massachusetts

Massachusetts net metering is governed under state law (M.G.L. c. 164, § 139) and administered through DPU regulations (220 CMR 18.00). For residential systems up to 25 kW, here's how the mechanics work:

Monthly credit banking. When your panels overproduce in a given month, you earn credits at the full retail rate. Those credits roll over month to month and apply against future bills — supply charges, delivery charges, and more.

Annual true-up. Credits accumulate throughout the year. At the end of the annual billing cycle — April for Eversource customers, March for National Grid and Unitil customers — any remaining unused credits are reconciled. Leftover balances are paid out at the wholesale avoided-cost rate, which typically runs around 3–5 cents per kWh.

Cap exemption for residential systems. Massachusetts has a statewide net metering cap that limits total participation within each utility territory. However, as of February 2025, residential systems up to 25 kW AC are automatically cap-exempt — meaning they qualify for net metering without needing a cap allocation, regardless of whether the utility's general cap is full. This is an important recent change; the previous threshold was 10 kW.

25-year term lock-in. Once your system is interconnected and enrolled in net metering, your credit structure is locked in for 25 years from the placed-in-service date. Even if Massachusetts changes its net metering rules in the future, your system keeps the terms that were in place when you enrolled.

Which Utilities Offer Net Metering in Massachusetts?

Massachusetts' three investor-owned utilities (IOUs) are all required to offer net metering:

• Eversource — serving eastern and western Massachusetts, including most of Greater Boston and the Pioneer Valley
• National Grid — serving Greater Boston, Worcester, and Cape Cod
• Unitil — serving the Fitchburg area and surrounding communities These three cover the majority of Massachusetts residents. The remainder are served by Municipal Light Plants (MLPs) — locally owned utilities like the Reading Municipal Light Department or Braintree Electric Light Department — and MLP policies vary. Some MLPs offer net metering programs comparable to the IOUs; others offer lower credit rates or different billing structures. If you're in MLP territory, it's worth calling your utility to understand exactly what's available.

Net Metering and the SMART Program

One thing that sets Massachusetts apart is that net metering isn't the only billing-level benefit running in parallel. The Solar Massachusetts Renewable Target (SMART) program pays solar owners a fixed rate per kWh of total generation for 20 years — completely separate from net metering credits, and received simultaneously.

Under SMART 3.0, residential customers earn approximately $0.03/kWh on all power their system produces, regardless of whether it's used on-site or exported. Your net metering credits and SMART payments operate independently — you receive both at once.

One important caveat as of mid-2026: the DPU is still reviewing the SMART 3.0 tariff (docket D.P.U. 25-175), and Final Statements of Qualification are not currently being issued until that review is complete. Payment start dates may lag behind system installation. Confirm the current program status with your installer before assuming when SMART payments will begin. For a full breakdown of SMART rates, adders, and how to maximize the combined value of both programs, see our Massachusetts Solar Incentives guide.

The Regulatory Picture Right Now

Massachusetts has maintained some of the most favorable net metering rules in the country for years. But 2026 brings a meaningful shift in the policy environment that every homeowner should understand.

In December 2025, the Massachusetts Department of Public Utilities (DPU) opened a formal investigation — docket D.P.U. 25-200 — examining electric rate design and, specifically, whether to reduce the value of net metering credits. The DPU's own filing noted it would compare Massachusetts rates to other states that "offer lower compensation."

This is an active regulatory proceeding, not a proposal that has been adopted. No changes are in effect yet. But the DPU investigation follows a well-worn path: California reduced its net metering credit by roughly 75% after a similar review; Illinois cut its by about half. The risk of a similar outcome in Massachusetts is real and worth taking seriously.

One specific proposal that has surfaced in the D.P.U. 25-200 context: a tiered structure that would preserve full retail-rate credits for systems up to 10 kW while reducing credits for systems between 10–25 kW to around 60% of retail. Comment periods ran through spring 2026. A final decision could come within 6–12 months.

This matters a great deal because of the 25-year lock-in rule. Homeowners who interconnect under the current rules are grandfathered into today's credit structure for the life of their system. Homeowners who wait may find themselves subject to a different — and less favorable — framework.

Net Metering and Battery Storage

A solar-plus-battery system still exports excess power to the grid under normal net metering rules when the battery is full. But in practice, pairing a battery means you'll export less, because the battery captures surplus that would otherwise leave your home. For most homeowners, that's actually the better trade — you're using your own electricity at night rather than buying it back from the grid.

Massachusetts also has a program called ConnectedSolutions, run by Eversource and National Grid, which pays battery owners to discharge their stored energy during peak grid demand events. The payments are among the highest battery demand response rates in the country, and they're completely separate from both net metering and SMART income — a third simultaneous income stream for solar-plus-storage homeowners.

One note: Unitil customers are not eligible for ConnectedSolutions. If you're in Unitil territory, a battery still provides real value through SMART battery adders and backup power, but demand response payments won't be part of the picture.

A Note on System Sizing

Massachusetts net metering works best when your system is sized to cover your actual consumption — not significantly more. At the annual true-up, remaining credits are paid out at wholesale avoided-cost rates of 3–5 cents per kWh, while you'd be buying replacement power at 28–32 cents per kWh. Deliberately oversizing to accumulate credits isn't a winning strategy on the margins.

A well-designed system aims to offset close to 100% of your annual usage. That's also what your installer will target based on your utility account history.

The Bottom Line

Massachusetts currently offers one of the strongest net metering programs in the country — full retail-rate credits, monthly rollover, a 25-year lock-in, and a cap exemption that now covers systems up to 25 kW. The SMART program stacks on top of that, adding a second income stream that runs independently for 20 years.

The open question is how long the current framework holds. The DPU's investigation into net metering credit values is real and active. The pattern in other states suggests that favorable policies do change — and that the homeowners who lock in current terms before a policy shift come out significantly ahead over the long run.

If you want a full picture of everything Massachusetts offers — SMART rates, tax exemptions, ConnectedSolutions, and what payback looks like in 2026 — our Massachusetts Solar Incentives guide covers it all.

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Lunex Power installs solar panel systems and home battery storage across Massachusetts, Florida, Connecticut, Rhode Island, Colorado, North Carolina, and South Carolina. Have questions about how net metering and SMART would stack up for your home? Talk to our team ».