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
An 8 kW solar system in Montana costs about $24,000 installed in 2026 (modeled at $3.00 per watt) and saves roughly $1,250 in its first year at the 12.5¢/kWh statewide average under retail net metering. That is a simple payback near 19 years, or about 17 years at NorthWestern Energy’s ~14.2¢/kWh. The 30% federal homeowner credit ended after 2025, and Montana’s residential solar income-tax credit has been repealed; a 10-year property-tax exemption remains.
Montana combines moderate sun, electricity prices well below the U.S. average and retail-rate net metering for systems up to 50 kW. That makes solar a long-horizon investment here: it works best for owners who plan to stay put, have a clear south-facing roof and can buy at a competitive price per watt. All results below come from our standard model and the Montana state data page; inputs are stated so you can check the math.
📋 Key Insights
How Much Sun Does Montana Get for Solar?
Our model assumes about 4.8 peak sun hours a day in Montana, so each kilowatt of panels produces roughly 1,440 kWh a year. Real output varies with latitude, elevation, snow, tilt and shading.
Peak sun hours are the equivalent number of hours at full-intensity sunlight (1,000 W per square meter), not daylight hours. NREL’s PVWatts tool gives an address-level estimate and is the right check before you sign anything.
Seasonality matters more than the annual average. Winter output is far below summer output, so a system sized for annual use runs a summer surplus and a winter deficit. That is why the net metering rules in the next section matter: credits banked in summer pay for winter usage.
⚖️ Policy & Net Metering
How Does Net Metering Work in Montana?
Montana law requires NorthWestern Energy and Montana-Dakota Utilities to offer net metering for systems up to 50 kW, crediting surplus generation to your next bill. That lets a right-sized system cover most of the bill, which is why our model uses an 87% bill offset.
How it works in practice:
When your panels produce more than you use, the excess flows to the grid and becomes a kWh credit on your next bill.
Credits carry forward through the 12-month net metering period, so summer surplus covers winter shortfall. Customers can choose to start the period in January, April, July or October.
Credit left at the end of the period is granted to the utility without payment, so production beyond your annual usage earns nothing. Aim for roughly 90–100% of your yearly kWh.
Fixed monthly customer charges are not offset by solar credits.
Montana does not currently allow aggregate or virtual net metering for the investor-owned utilities.
Electric cooperatives adopt net metering policies voluntarily, so rules and size limits vary by co-op. Get the written tariff and interconnection steps before sizing a system. Try the solar net metering calculator to see how credits roll across Montana’s seasons. Source: Montana Legislature net metering briefings, Montana Renewable Energy Association, NorthWestern Energy.
💰 System Cost
How Much Do Solar Panels Cost in Montana in 2026?
An 8 kW system costs about $24,000 at a modeled $3.00 per watt, and a 2026 buyer pays the full price because no federal or state credit applies. Treat $3.00/W as a planning assumption, not a quote.
Montana solar cost and payback, 2026 (modeled)
Input or result
Value
System size
8.0 kW (20 × 400 W panels)
Installed price (assumption)
$3.00/W → $24,000
Peak sun hours (assumption)
4.8
Annual production (8 kW × 4.8 × 365 × 0.82)
~11,490 kWh
Residential rate, statewide average
12.5¢/kWh (EIA reports ~12.3¢ for April 2026)
Bill offset (retail net metering)
0.87
Year-1 savings (11,490 × $0.125 × 0.87)
~$1,250
Simple payback ($24,000 ÷ $1,250)
~19.2 years
Same system at NorthWestern Energy’s ~14.2¢/kWh
~$1,420/yr, payback ~16.9 years
25-year net savings, rates +3%/yr, 0.5%/yr degradation
~$18,600
25-year net savings, rates flat
~$5,400
Assumptions from our methodology; the modeled home uses about what the system produces (~$120/month bill). Your quote and usage will differ.
Data visualization
Cumulative net position of an 8 kW Montana system after a $24,000 cost. Modeled at 12.5¢/kWh with 3% or 0% yearly rate increases, no federal credit. Source: EIA rates; Green Energy Calculators model.
Chart summary: If electricity rates rise 3% a year, cumulative savings pass the $24,000 cost in year 16 and reach about $18,600 net by year 25. If rates stay flat, the system breaks even in year 21 and nets about $5,400 by year 25. The outcome depends heavily on future rate increases, which no model can guarantee.
Data visualization
Simple payback for an 8 kW Montana system runs 13.5 to 21.8 years across $2.40 to $3.40 per watt. Rates: 12.5¢/kWh statewide average and 14.2¢/kWh NorthWestern Energy average (EIA-861, 2024); no incentives.
Chart summary: Price per watt and your utility rate move payback more than anything else. At $3.00/W, payback is about 19.2 years at 12.5¢/kWh and about 16.9 years at 14.2¢/kWh. Each $0.20/W off the quote saves $1,600 and shortens payback by roughly 1.0–1.3 years.
How much did the end of the federal credit change Montana payback? Before 2026, the 30% §25D credit would have lowered this system to about $16,800, a payback near 13.4 years at 12.5¢/kWh. For the same system installed in 2026, payback is about 19.2 years.
Montana sizing examples (4.8 peak sun hours)
Annual use
System size
Panels (400 W)
Installed cost ($3.00/W)
9,000 kWh
~6.3 kW
16
~$18,800
11,500 kWh
~8.0 kW
20
~$24,000
14,000 kWh
~9.7 kW
25
~$29,200
Formula: kW = annual kWh ÷ (4.8 × 365 × 0.82). Cost shown is for the calculated kW, before rounding to whole panels.
Run the numbers for your state
The savings calculator loads your state's average electricity rate, sun hours and net-metering rule. Then enter your own bill and installer quote.
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🏛️ Incentives
What Solar Incentives Are Left in Montana in 2026?
A Montana homeowner buying solar in 2026 gets no federal credit and no state income-tax credit; what remains is a 10-year property-tax exemption and access to a state loan program. Business and farm projects still have some federal options.
What ended (federal):
§25D Residential Clean Energy Credit (30%): ended for expenditures after Dec 31, 2025, under the One Big Beautiful Bill Act (Public Law 119-21, signed July 4, 2025). If your installation was completed in 2025, claim it on your 2025 return with Form 5695; unused credit from earlier years can still carry forward. Details: IRS OBBB FAQ and our federal solar tax credit guide.
§25C efficiency credits ended after Dec 31, 2025; the §30C EV charger credit ended for property placed in service after June 30, 2026.
Montana (state):
Residential alternative energy income-tax credit (formerly up to $500): repealed. Montana’s Department of Environmental Quality notes the Legislature eliminated energy-related tax credits.
Property-tax exemption: up to $20,000 of added value on a single-family home is exempt for 10 years after installation. Apply with Form AB-14 through the Montana Department of Revenue.
Alternative Energy Revolving Loan Program (DEQ): low-interest loans up to $40,000 with repayment up to ten years; funding is limited and requires an application.
Montana has no general statewide sales tax, so there is no sales tax on equipment.
Who else may still benefit:
Leases and PPAs: the provider may claim §48E for solar that begins construction by July 4, 2026, or is placed in service by Dec 31, 2027, and may pass part of that value through in the price. No specific discount is guaranteed.
Farms and rural small businesses: ask about USDA REAP grants (funding rounds vary) and the §48E credit; depreciation rules changed in 2025, so confirm with a tax professional. The agricultural solar calculator models farm projects.
Nonprofits, tribes, schools and local governments: elective (“direct”) pay under §6417 may apply for qualifying §48E projects within the same deadlines.
Check DSIRE, the Montana Department of Revenue and your utility or co-op for local programs. This is general information, not tax advice; confirm with a tax professional.
✅ Worth It?
Is Solar Worth It in Montana in 2026?
Solar can still pay off in Montana, but with a roughly 17–19 year payback it suits owners with a long horizon, a strong roof and a competitive quote; the modeled 25-year net gain is about $18,600 if rates rise 3% a year and about $5,400 if they stay flat. Without solar, the modeled household pays about $52,400 in electricity over 25 years (3%/yr increases). With solar, installed cost plus remaining bills total about $33,800.
What moves the answer:
Price per watt. At $2.60/W the same system costs $20,800 and pays back in about 16.6 years at 12.5¢/kWh.
Your utility rate. Montana rates differ by provider; NorthWestern Energy’s average residential price is higher than the statewide average, which shortens payback. A co-op with a lower rate or a different crediting policy would lengthen it.
Financing. A loan adds interest and can consume much of the 25-year margin; compare cash, home-equity and solar-loan totals with the solar loan calculator.
How long you stay. If you might sell within 10–12 years, you are unlikely to recover the cost through bill savings alone.
Batteries add substantial cost and receive no federal homeowner credit in 2026. They make sense mainly for backup during outages, not for bill savings under retail net metering. Put your actual bill into the solar savings calculator before you talk to installers.
Sources: IRS OBBB FAQ (federal policy); EIA (rates; Form EIA-861); Montana Legislature, Montana DEQ and Montana Department of Revenue (state programs); NREL PVWatts (production tool). Model details: methodology.
Solar vs utility company · 25-year comparison
25-year totals: 3%/yr rate increases, 0.5%/yr degradation, no federal credit. Methodology
In our model, an 8 kW system (20 panels at 400 W) costs about $24,000 at $3.00 per watt before any incentive. To size a system, divide annual kWh by about 1,437 (4.8 sun hours × 365 × 0.82): a home using 12,000 kWh a year needs about 8.4 kW, or 21 panels. The $3.00/W price is a modeling assumption, so collect several local quotes and ask for an NREL PVWatts production estimate for your address.
No. The 30% Residential Clean Energy Credit (§25D) ended for expenditures made after December 31, 2025, under Public Law 119-21. If your system was installed in 2025, claim the credit on your 2025 return with Form 5695; unused credit from earlier years can still carry forward. A system installed in 2026 gets no federal homeowner credit.
About 19 years in our 2026 model at the 12.5¢/kWh statewide average: $24,000 ÷ ~$1,250 of year-one savings ≈ 19.2 years. NorthWestern Energy customers pay closer to 14.2¢/kWh (EIA-861, 2024), which shortens payback to roughly 17 years. If electricity rates rise 3% a year, cumulative savings pass the system cost around year 16.
Montana law requires NorthWestern Energy and Montana-Dakota Utilities to offer net metering for systems up to 50 kW. Surplus generation becomes a kWh credit on your next bill at the retail rate, and credit left at the end of the 12-month period is granted to the utility without payment. Size your system to produce about 90–100% of your annual use. Electric cooperatives adopt net metering voluntarily, so ask your co-op for its written tariff.
Montana's residential alternative energy income-tax credit (formerly up to $500) has been repealed and is not available for new installations. Still available: a property-tax exemption that excludes up to $20,000 of added value for 10 years on a single-family home (Form AB-14 from the Montana Department of Revenue), and low-interest loans of up to $40,000 through the DEQ Alternative Energy Revolving Loan Program. Confirm current terms with the agencies; this is not tax advice.
$86/month electric bill by state
System size and payback vary by electricity rate and sun hours — see your state.
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.