Waltham Solar in 2026: Eversource Net Metering, the SMART Program, and What It Costs

Updated for 2026.

Waltham homeowners pay some of the highest electricity prices in the country, and that is the single biggest reason rooftop solar pays off here. Updated for 2026, this page covers what solar actually costs on a Waltham roof, how Eversource credits the power you send back, the Massachusetts incentives you may qualify for, and one local detail that trips people up: the City of Waltham runs its own electricity supply program, but your solar credits still run through Eversource. You can read the whole thing, or check your address in about a minute.

What matters most for Waltham solar in 2026

• Your electric utility is Eversource, and that is what makes solar pay. Massachusetts residential electricity averages about 30.21 cents per kWh (EIA, as of March 2026), nearly double the national average, and Eversource’s Eastern Massachusetts customers sit at the high end of that range.
• A typical 6 kW Waltham system makes about 7,829 kWh a year. That is a modeled estimate for a Waltham roof (NREL PVWatts v8, 6 kW, ZIP 02451, as of July 2026), or roughly 1,305 kWh for every kW you install.
• Net metering credits a typical home near full retail value. Residential systems of 25 kW or less are cap-exempt and earn dollar credits that roll forward month to month (Mass.gov net-metering guide, as of July 2026).
• SMART adds a separate per-kWh payment to the system owner. Under SMART 3.0, standard residential systems earn about 3 cents per kWh over a 20-year term (Mass.gov SMART 3.0, as of July 2026).
• Estimated payback runs about 7 years on bill savings alone for a typical cash-bought 6 kW system, before counting SMART income (our own estimate, method and inputs shown below).
• The 30% federal homeowner credit (Section 25D) ended after December 31, 2025 (IRS, as of 2026), so a Waltham homeowner who buys in 2026 cannot claim it.

Waltham solar by the numbers

• Massachusetts residential electricity rate: about 30.21 cents per kWh, as of March 2026 (EIA).
• Modeled production for a 6 kW Waltham system: about 7,829 kWh per year, as of July 2026 (NREL PVWatts v8, ZIP 02451).
• Estimated first-year bill savings for that system: about $2,365, as of 2026 (our estimate: production times the state average rate).
• Estimated simple payback on bill savings alone: about 7 years, as of 2026 (our estimate, inputs below).
• SMART 3.0 standard residential incentive: about 3 cents per kWh for 20 years, as of July 2026 (Mass.gov).

Why Waltham’s Eversource rates make solar worth it

The reason solar pays in Waltham is the price of the power it replaces. Massachusetts residential electricity averages about 30.21 cents per kWh (EIA, as of March 2026), one of the highest rates in the country, and Eversource’s Eastern Massachusetts customers, Waltham included, sit at the top end of that range. Every kilowatt-hour your roof makes offsets an expensive one you would otherwise buy from the grid, so a Waltham home spending $150 or more a month on electricity is usually a strong solar candidate. For the exact cents on your own bill, read the supply and delivery lines on your Eversource statement, because both reset on a schedule.

Your production is what turns that high rate into savings. A 6 kW system on a Waltham roof is modeled to make about 7,829 kWh a year (NREL PVWatts v8, ZIP 02451, as of July 2026), which works out to roughly 1,305 kWh for each kW installed. Output depends on your roof’s pitch, shading, and orientation, so shade from a neighbor’s oak or a taller two-family next door will pull your number down. The table below scales the PVWatts figure to a few common system sizes so you can see the range before you get a quote.

System size	Estimated annual production	Estimated first-year bill value
5 kW	about 6,525 kWh	about $1,971
6 kW	about 7,829 kWh	about $2,365
8 kW	about 10,440 kWh	about $3,154
10 kW	about 13,050 kWh	about $3,942

Our estimate. Production scaled from the NREL PVWatts v8 run for Waltham 02451 (about 1,305 kWh per kW per year); bill value is production times the Massachusetts average residential rate of 30.21 cents per kWh (EIA, March 2026). Your roof, shading, and usage change these numbers, so treat them as a starting point, not a quote.

What electric company does Waltham use for solar?

Waltham’s electric utility is Eversource, in its Eastern Massachusetts territory. Massachusetts assigns each utility an exclusive electric delivery territory, so there is no overlap at a given address, and Waltham, ZIP codes 02451, 02452, and 02453, is served by NSTAR Electric doing business as Eversource (Mass.gov Electricity Providers, as of July 2026). That matters for solar because your net metering, your interconnection application, and your Permission to Operate all run through Eversource, not through any supply company you may buy power from. For the statewide mechanics behind all of this, see our Eversource Massachusetts solar guide and the Massachusetts solar guide.

Here is the Waltham-specific wrinkle worth understanding. The City of Waltham runs its own municipal electricity supply program, Waltham Community Electricity, which buys power in bulk for residents and sets the supply rate on many local bills (City of Waltham Community Electricity, as of June 2026). Under Massachusetts law a municipal aggregation like this only procures the supply portion of your bill; Eversource still owns the wires, delivers the power, reads the meter, sends the bill, and administers net metering. So whether you are on Waltham Community Electricity or on Eversource Basic Service, your solar credits work the same way and are handled by Eversource. The high local rate is what drives your payback either way.

How Eversource net metering credits your Waltham solar

Net metering is the engine of your savings, and for a normal Waltham home it credits near full retail value. Massachusetts net metering is set by state law and regulation, not by the utility, and after the state raised the residential threshold from 10 kW to 25 kW AC (DPU order D.P.U. 23-140-A), a residential system of 25 kW or less is cap-exempt and never shut out (Mass.gov net-metering guide, as of July 2026). When your panels make more than you use, the excess flows to the grid and Eversource posts a credit to your account in dollars, valued to offset your supply, delivery, and customer charges, which is why it lands near the full retail rate rather than a reduced wholesale rate.

Those credits roll forward, and for a typical home they keep rolling. Unused net-metering credits carry over month to month on your Eversource account. For a standard residential system of 25 kW or less there is no automatic year-end cash-out at a lower rate; the annual avoided-cost true-up that some guides describe applies to larger on-site-load facilities, not to a normal rooftop system (Mass.gov net-metering guide, as of July 2026). The practical takeaway is to size your system close to your yearly usage. Building a much larger array than you consume banks credits you may never work through, since a typical residential account is not written a check for a permanent surplus. For the mechanics in plain language, see how net metering credits your solar exports.

What you earn	How it is valued	Who receives it
Monthly net-metering credits	Near full retail value, tracked in dollars, rolled forward	The Eversource account holder
Rolled-forward surplus	Carries to the next month at the same value, no automatic year-end cash-out for a 25 kW or smaller home system	The account holder
SMART payment	A separate per-kWh incentive over a 20-year term	The system owner

Massachusetts incentives on a Waltham Eversource account

Beyond net metering, a Waltham homeowner stacks the same statewide Massachusetts benefits as the rest of the state. These go to the system owner, so on a lease or a PPA the company that owns the panels keeps the incentive, while the net-metering credit still follows your Eversource account. We keep the full statewide detail on our Massachusetts net metering and SMART guide rather than repeating all of it here.

• SMART (Solar Massachusetts Renewable Target), the state’s per-kWh incentive, now running as SMART 3.0 under the Department of Energy Resources. It pays the system owner about 3 cents per kWh for a standard residential system and about 6 cents per kWh for income-eligible customers, over a 20-year term, paid monthly by Eversource (Mass.gov SMART 3.0, as of July 2026). SMART and your net-metering credits interact under DOER and DPU rules rather than simply adding together, so ask your installer which combination applies to your specific system and confirm the current per-kWh value for your block.
• The Massachusetts Residential Energy Credit (Schedule EC), a state income-tax credit worth 15% of the net cost of the system, capped at $1,000 (Mass.gov 830 CMR 62.6.1, as of July 2026).
• A 100% sales-tax exemption on qualifying residential solar equipment, off the state’s 6.25% sales tax, certified with Form ST-12 (Mass.gov Sales and Use Tax, as of July 2026).
• A 20-year property-tax exemption on the added home value from a qualifying solar system, under Clause 45, so the value your panels add is not taxed for that period (Mass.gov, M.G.L. c.59 s.5, as of July 2026).

Program	What it gives you	Who claims it
SMART 3.0	About 3 cents per kWh (about 6 cents low-income), 20-year term	The system owner
Net metering	Near-full-retail dollar credits, rolled forward	The Eversource account holder
Schedule EC state credit	15% of net system cost, capped at $1,000	The homeowner-owner, on the state return
Sales-tax exemption	100% off the 6.25% state sales tax on equipment	The buyer, at purchase
Property-tax exemption	20 years on the added home value (Clause 45)	The property owner

What the federal tax-credit change means for Waltham

The federal homeowner credit is gone, but the Massachusetts programs are not. The 30% federal Residential Clean Energy Credit (Section 25D) ended for systems placed in service after December 31, 2025, under the One Big Beautiful Bill Act, so a Waltham homeowner who buys solar with cash or a loan in 2026 cannot claim it (IRS; SEIA, as of 2026). Eligibility keys off the date your system is placed in service, not the date you signed or paid, so a 2026 installation does not qualify. You will still see installer pages and search results asking whether the 30% credit is going away; the accurate answer for 2026 is that the homeowner version already ended. For the full timeline, see what the federal solar tax credit change means in 2026.

One federal exception exists, and it is not yours to claim. A separate commercial credit, Section 48E, can apply to a leased or PPA system and is claimed by the business that owns the panels, not by the homeowner (IRS Clean Electricity Investment Credit, as of 2026). On a leased system you do not file for a federal credit yourself; the company that owns the equipment does. The 25D homeowner credit, by contrast, ended for systems placed in service after December 31, 2025. MySolarFY does not provide tax advice, so confirm your own situation with a tax professional.

What a Waltham solar system costs and when it pays back

Here is the original math for a typical Waltham home, using the rate and production figures above. A 6 kW system at the Massachusetts average installed price of about $3.00 per watt runs near $18,000 before incentives (EnergySage Massachusetts, as of June 2026). The Schedule EC state credit takes $1,000 off, there is no federal homeowner credit in 2026, and the system is modeled to save about $2,365 in the first year through net metering. That is a simple payback of about seven years on bill savings alone, before you count a dime of SMART income.

Line item	Estimate	Source or basis
System size	6 kW	Typical Waltham home
Installed cost at about $3.00 per watt	about $18,000	EnergySage MA, June 2026
Massachusetts Schedule EC state credit	minus $1,000	Mass.gov 830 CMR 62.6.1
Federal 25D homeowner credit	$0 (ended 12/31/2025)	IRS
Estimated net cost	about $17,000	Our calculation
Estimated first-year bill savings	about $2,365	7,829 kWh times 30.21 cents (PVWatts x EIA)
Estimated simple payback (bill savings only)	about 7 years	Our calculation
SMART income, added separately	about $235 per year	7,829 kWh times about 3 cents (Mass.gov)

Going solar on a Waltham home

Waltham’s housing mix is what shapes its solar projects. The neighborhoods near downtown and Moody Street lean toward older two-family and multi-family homes, while the west side and Piety Corner have more single-family houses with larger roofs, and each raises a different check. Older homes more often run a 100-amp electrical service panel that may need an upgrade to carry a modern system, especially if you also want a battery, an EV charger, or a heat pump. On a two-family or a shared roof, you will also want your co-owner’s sign-off and a clear roof-rights understanding before panels go up.

• Roof condition and age. If your roof is within a few years of replacement, it is usually cheaper to reroof first than to remove and reset panels later.
• Service panel capacity. A 100-amp panel plus solar and a battery can require a service upgrade; a good installer flags this in the site visit.
• Shading. Waltham’s mature street trees and taller neighboring homes can shade a roof; a shade study tells you whether fewer high-efficiency panels beat a larger array.
• Permitting. Waltham solar installs run through the city’s Inspectional Services and an Eversource interconnection review; an experienced local installer manages both.

Paying for solar in Waltham: cash, loan, lease, or PPA

There is no single right way to pay for solar. The best fit depends on whether you want to own the system and claim the state incentives yourself, or avoid an up-front cost. A lease or PPA can mean no up-front cost for eligible homeowners, but it is a long-term agreement with monthly payments, not free solar, and the company that owns the panels, not you, collects the SMART payment and the state tax credit.

Path	Up-front cost	Who keeps SMART and the state credit	Best when
Cash purchase	Full system cost	You, the owner	You want the fastest payback and the most lifetime savings
Solar loan	Little to none, financed	You, the owner	You want ownership without paying cash up front
Lease or PPA	$0-up-front where eligible	The third-party owner	You prefer no up-front cost and a simpler, fixed monthly bill

How to choose a solar installer in Waltham

Waltham sits in a deep Greater Boston installer market, from local Massachusetts companies to national brands, which is good for you because it means real competition on price and service. Rather than chasing a “best installer” list, screen any company against objective criteria:

• NABCEP certification, the industry’s professional standard for photovoltaic installers.
• A valid Massachusetts Home Improvement Contractor registration and proper electrical licensing.
• A clear workmanship and equipment warranty in writing.
• Real experience with Eversource interconnection and Waltham permitting, so your paperwork and Permission to Operate go smoothly.
• A written production estimate and a transparent quote that uses today’s SMART value, not an old one. For a checklist, see the right questions to ask a solar installer.

MySolarFY matches you with licensed installers that serve your area so you can compare real local quotes side by side, with no obligation. See how MySolarFY works and our data and methodology for how we research these pages. You can also compare nearby Middlesex options in Cambridge, Newton, and Framingham.

Check which solar programs are available at your Waltham address →

Frequently asked questions

Is solar worth it in Waltham in 2026? For most owner-occupied Waltham homes with decent sun, yes. Massachusetts residential electricity averages about 30.21 cents per kWh (EIA, as of March 2026), among the highest in the country, and Eversource’s Eastern Massachusetts rates sit at the top of that range, so every kilowatt-hour your roof makes offsets an expensive grid one. A typical 6 kW system is modeled to make about 7,829 kWh a year, worth roughly $2,365 at that rate, for an estimated payback near seven years on bill savings alone. Savings are not guaranteed and depend on your roof, usage, and how you pay, but the high local rate is what makes Waltham a strong solar market.

What electric company does Waltham, MA use? Eversource, in its Eastern Massachusetts territory. Waltham’s ZIP codes 02451, 02452, and 02453 are all served by NSTAR Electric doing business as Eversource, and Massachusetts electric territories do not overlap, so your net metering and interconnection are handled by Eversource (Mass.gov Electricity Providers, as of July 2026). If your supply comes through Waltham Community Electricity, the city’s municipal aggregation, that only sets the supply price; Eversource still delivers the power, reads your meter, and administers your solar credits.

Does Waltham Community Electricity change my solar net metering? No. Waltham Community Electricity is a municipal aggregation that buys the supply portion of your electricity in bulk, but under Massachusetts law it does not touch delivery or net metering (City of Waltham, as of June 2026). Eversource remains your distribution utility, so it still meters your exports, posts your net-metering credits, and runs your interconnection. Whether you stay on Waltham Community Electricity or switch to Eversource Basic Service, your solar credits are calculated and applied the same way.

How does net metering work with Eversource in Waltham? When your panels produce more than you use, the extra flows to the grid and Eversource credits your account in dollars near the full retail rate, and those credits roll forward month to month (Mass.gov net-metering guide, as of July 2026). Residential systems of 25 kW or less are cap-exempt, after the state raised the threshold from 10 kW to 25 kW AC, so a typical home always qualifies for the standard credit, and there is no automatic year-end cash-out at a lower rate for a system that size. The smart move is to size your system close to your annual usage so you use the credits you earn.

What happened to the federal solar tax credit? The 30% federal Residential Clean Energy Credit (Section 25D) ended for systems placed in service after December 31, 2025, under the One Big Beautiful Bill Act, so a Waltham homeowner who buys solar in 2026 with cash or a loan cannot claim it (IRS, as of 2026). Eligibility keys off the date the system is placed in service, not when you signed. A separate commercial credit, Section 48E, can apply to leased and PPA systems, but the business that owns the system claims it, not the homeowner. Massachusetts net metering, SMART, and the state tax benefits were not affected, so at Waltham’s high rates the local payback case still holds.

Can I get solar with no up-front cost in Waltham? Some homeowners can, through a lease or power purchase agreement (PPA) where eligible, which can mean no out-of-pocket cost at installation in exchange for monthly payments. This is not free solar; it is a long-term agreement, typically 20 to 25 years, and total payments may exceed the cost of a cash purchase. On a lease or PPA the third-party owner, not you, collects the SMART payment and the state tax credit, while your benefit is a lower or fixed power price. If you want to own the system and capture those incentives yourself, a cash purchase or a solar loan is the path that keeps them. Check what you qualify for before deciding.

Reviewed by the SolarFY Editor on July 4, 2026. Figures were verified against the linked Massachusetts (Mass.gov / DOER / DPU), City of Waltham, EIA, NREL, and IRS sources as of July 2026. Net-metering values, the SMART 3.0 per-kWh rate and 20-year term, and installed prices can change, so confirm current terms with Eversource, the City of Waltham, and Mass.gov before you decide. MySolarFY does not provide tax or financial advice; consult a licensed professional about your own situation. Learn more about the MySolarFY team and how we work.

MySolarFY is a free service that matches homeowners with licensed solar installers. We are not an installer, financing company, tax advisor, or government program. “No up-front cost” refers to qualifying lease or PPA financing, where eligible homeowners may have no out-of-pocket cost at installation. Lease and PPA terms typically run 20 to 25 years, may include an annual price escalator, and total payments may exceed the cost of a cash purchase; on a lease or PPA the SMART payment and tax benefits go to the company that owns the system, not the homeowner. Homeowners do not get the federal residential credit (Section 25D) that ended after December 31, 2025. Solar panels are not free and monthly payments apply. Eligibility, savings, incentives, and rates vary and are not guaranteed. See our full disclaimer.