Scenario: a $250/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 $250/month electricity bill in Montana represents roughly 1,792 kWh per month at the state average rate of 13.95¢/kWh (EIA, Jan–Jul 2026 year-to-date). With 4.8 peak sun hours per day, offsetting that usage takes about a 15.0 kW solar system — roughly 38 panels at 400W — costing about $44,900 installed. Because the 30% federal tax credit ended for systems installed after 2025 and Montana has full retail net metering, simple payback is about 17.2 years, with an estimated $44,100 net over 25 years.
How Many Solar Panels for a $250 Electric Bill in Montana?
Montana 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 $250/month bill in Montana:
Annual usage: ~21,505 kWh/year
Peak sun hours: 4.8 h/day (Montana)
System size:15.0 kW DC (~38 × 400W panels)
Metric
Montana
US average
Rate
13.95¢/kWh
18.19¢/kWh
Sun hours
4.8 h/day
4.5 h/day
System size
15.0 kW
12.2 kW
Panels (400W)
38
31
Montana requires a larger system than the national average for the same dollar bill because higher consumption at lower rates. 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 $250/Month Bill in Montana in 2026?
At about $3.00/W installed (a blended 2026 US price; marketplace quotes often run lower), a 15.0 kW system in Montana costs about $44,900.
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 (15.0 kW)
$44,900
Federal credit (25D) for 2026 installs
$0
Your cost before state/local incentives
$44,900
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 $250 Bill in Montana?
Simple payback divides installed cost by first-year bill savings. Montana (NorthWestern Energy) offers retail net metering for systems up to 50 kW. We therefore assume solar offsets about 87% of a $250/month bill in Montana — roughly $2,610/year — for a simple payback of about 17.2 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 $44,100. 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 $250/month electric bill: 3%/yr rate increases, 0.5%/yr degradation, no federal credit. Methodology
Montana Solar Incentives for a $250/Month Electric Bill
State and local incentives: Montana offers an alternative energy system income-tax credit of up to $500 per taxpayer and a 10-year property-tax exemption for residential solar.
Net metering: Montana (NorthWestern Energy) offers retail net metering for systems up to 50 kW.
Check DSIRE and our Montana solar page for current rebates, net metering rules, and utility-specific programs before signing an install contract.
⚡ System Size
Montana vs US Average: $250/Month Bill Comparison
Montana
US average
Monthly bill
$250
$250
System size
15.0 kW
12.2 kW
Installed cost
$44,900
$36,700
Bill offset assumed
87%
75% (blended)
Simple payback
17.2 yrs
16.3 yrs
25-year net savings
$44,100
$40,000
Bottom line: A $250/month bill in Montana is a marginal solar candidate with about 17.2-year payback in 2026. Calculate your Montana savings or compare all states on the $250 bill hub.
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At Montana's average rate of 13.95¢/kWh and 4.8 peak sun hours, a $250/month bill (~21,505 kWh/year) typically requires a 15.0 kW system — about 38 panels at 400W each. Use our solar system size calculator with your ZIP for a roof-specific estimate.
A 15.0 kW system in Montana costs roughly $44,900 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. Montana offers an alternative energy system income-tax credit of up to $500 per taxpayer and a 10-year property-tax exemption for residential solar.
At $44,900 installed and ~$2,610/year in bill savings, simple payback in Montana is about 17.2 years. Montana (NorthWestern Energy) offers retail net metering for systems up to 50 kW.
With about 17.2-year payback and roughly $44,100 in estimated 25-year net savings, a $250/month bill in Montana is a marginal case for buying solar in 2026. See the [Montana solar page](/states/mt/) for net metering and incentive details.
The US average needs a 12.2 kW system at 16.3-year payback. Montana needs 15.0 kW with 17.2-year payback — driven by Montana's 13.95¢/kWh rate and 4.8 daily sun hours.
13.95¢/kWh — Montana 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
4.8 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. Montana (NorthWestern Energy) offers retail net metering for systems up to 50 kW.
Estimates only — not tax, legal or financial advice. Get at least three installer quotes and confirm incentives with your utility and a tax professional.