Scenario: a $125/month electric bill. Assumes 3%/yr rate increases, 0.5%/yr panel degradation and no federal tax credit (the 30% §25D credit ended for systems installed after Dec 31, 2025). How we calculate
Data approachEIA rates · NREL sun hours · 2026 federal policy · methodology
A $125/month electricity bill in Massachusetts represents roughly 415 kWh per month at the state average rate of 30.14¢/kWh (EIA, Jan–Jul 2026 year-to-date). With 4.2 peak sun hours per day, offsetting that usage takes about a 4.0 kW solar system — roughly 10 panels at 400W — costing about $11,900 installed. Because the 30% federal tax credit ended for systems installed after 2025 and Massachusetts has full retail net metering, simple payback is about 9.1 years, with an estimated $32,600 net over 25 years.
How Many Solar Panels for a $125 Electric Bill in Massachusetts?
Massachusetts electricity rates and sun hours change the math versus the US average. The sizing formula:
System size (kW) = Annual kWh ÷ (Peak sun hours × 365 × 0.82)
For a $125/month bill in Massachusetts:
Annual usage: ~4,977 kWh/year
Peak sun hours: 4.2 h/day (Massachusetts)
System size:4.0 kW DC (~10 × 400W panels)
Metric
Massachusetts
US average
Rate
30.14¢/kWh
18.19¢/kWh
Sun hours
4.2 h/day
4.5 h/day
System size
4.0 kW
6.1 kW
Panels (400W)
10
16
Massachusetts requires a smaller system than the national average for the same dollar bill because higher rates reduce required kWh. Use our solar system size calculator with your ZIP code for a roof-specific result.
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💰 System Cost
What Does Solar Cost for a $125/Month Bill in Massachusetts in 2026?
At about $3.00/W installed (a blended 2026 US price; marketplace quotes often run lower), a 4.0 kW system in Massachusetts costs about $11,900.
The 30% federal Residential Clean Energy Credit (IRC §25D) ended for systems installed after December 31, 2025, so a solar system you buy and install in 2026 gets no federal tax credit. Leases and PPAs are different: the installer that owns the system can still claim the commercial §48E credit for systems placed in service by the end of 2027 and may pass part of that value on through a lower monthly price.
Cost line
Amount
Installed cost (4.0 kW)
$11,900
Federal credit (25D) for 2026 installs
$0
Your cost before state/local incentives
$11,900
Getting three or more quotes matters more than ever without the federal credit: installed prices for the same system often differ by 20–30%.
📈 Payback Period
How Long Is Solar Payback on a $125 Bill in Massachusetts?
Simple payback divides installed cost by first-year bill savings. Massachusetts offers retail-rate net metering for residential systems plus SMART program payments. We therefore assume solar offsets about 87% of a $125/month bill in Massachusetts — roughly $1,305/year — for a simple payback of about 9.1 years.
Over 25 years, with 3% annual rate increases and 0.5%/year panel degradation, cumulative bill savings minus the installed cost come to about $32,600. Full retail net metering means each kWh you produce is worth close to your retail rate. Model your own numbers in our solar payback calculator.
Solar vs utility company · 25-year comparison
25-year totals for a $125/month electric bill: 3%/yr rate increases, 0.5%/yr degradation, no federal credit. Methodology
Massachusetts Solar Incentives for a $125/Month Electric Bill
State and local incentives: Massachusetts offers a 15% state income-tax credit (up to $1,000), SMART program production payments, and sales- and property-tax exemptions for residential solar.
Net metering: Massachusetts offers retail-rate net metering for residential systems plus SMART program payments.
Check DSIRE and our Massachusetts solar page for current rebates, net metering rules, and utility-specific programs before signing an install contract.
⚡ System Size
Massachusetts vs US Average: $125/Month Bill Comparison
Direct answers for US homeowners in Massachusetts.
At Massachusetts's average rate of 30.14¢/kWh and 4.2 peak sun hours, a $125/month bill (~4,977 kWh/year) typically requires a 4.0 kW system — about 10 panels at 400W each. Use our solar system size calculator with your ZIP for a roof-specific estimate.
A 4.0 kW system in Massachusetts costs roughly $11,900 installed at about $3.00 per watt. The 30% federal tax credit (25D) ended for systems installed after December 31, 2025, so there is no federal credit for a system you buy in 2026. Massachusetts offers a 15% state income-tax credit (up to $1,000), SMART program production payments, and sales- and property-tax exemptions for residential solar.
At $11,900 installed and ~$1,305/year in bill savings, simple payback in Massachusetts is about 9.1 years. Massachusetts offers retail-rate net metering for residential systems plus SMART program payments.
With about 9.1-year payback and roughly $32,600 in estimated 25-year net savings, a $125/month bill in Massachusetts is a strong case for buying solar in 2026. See the [Massachusetts solar page](/states/ma/) for net metering and incentive details.
The US average needs a 6.1 kW system at 16.3-year payback. Massachusetts needs 4.0 kW with 9.1-year payback — driven by Massachusetts's 30.14¢/kWh rate and 4.2 daily sun hours.
30.14¢/kWh — Massachusetts average residential price. Source: EIA Electric Power Monthly, Table 5.6.B (year-to-date through July 2026), residential average retail price (July 2026) (EIA)
Solar production
4.2 peak sun hours/day × 0.82 system derate. Approximate state-average daily solar resource (peak sun hours) based on NREL solar resource data (NSRDB); not location-specific — use NREL PVWatts for an address-level estimate. (NREL PVWatts)
Installed price
$3.00 per watt before incentives. Blended 2026 US residential installed price used by this site; EnergySage marketplace reported about $2.60/W (mid-2026); full-market medians are higher.
Federal tax credit
$0 for homeowner-owned systems installed in 2026 — the 30% §25D credit ended Dec 31, 2025 (IRS)
Net metering
Full retail net metering — solar assumed to offset 87% of the bill. Massachusetts offers retail-rate net metering for residential systems plus SMART program payments.
Estimates only — not tax, legal or financial advice. Get at least three installer quotes and confirm incentives with your utility and a tax professional.