Written by Dean Mahmoud, CEO, and checked by Trevor Guilday, founder.Prices from the September 2026 Cost Index. Updated October 14, 2026.
A typical Montana home system is 7.13 kW and costs about $19,465 in cash at $2.73 per watt. It pays for itself in about 16.6 years if every credit gets used, or 25.6 years if half your exports are lost at the yearly reset you choose.
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Extra solar power becomes a kWh credit on your next bill, 1 for 1. Credits keep rolling for 12 months. Then any you have not used go to the utility with no payment. State law lets you choose the day that 12-month credit year starts.
For a home that banks credits in summer and uses them in winter, the balance is usually lowest here, so little is lost.
The balance can be at its highest, and it goes to the utility just before winter would have used it.
Part of the summer credit may still be unused when the year closes.
Credits from spring are lost just as the strongest months begin.
Your home may differ. NorthWestern bills show a graph of your last 12 months of use; look at it before the form is filled in. At NorthWestern the month goes on Exhibit A of the interconnection request your installer files, and you can change it once. After that it is permanent.
Power beyond your own yearly use is never paid for. Example: your panels make 11,000 kWh in a year and your home uses 10,000 kWh. At least 1,000 kWh are left at the reset, and the utility gets them for free. The typical 7.13 kW system makes about 10,043 kWh a year, so compare that figure with a full year of your bills.
Credits do not move with you either. NorthWestern says any balance left when your agreement ends or the home changes owner goes to the utility with no payment.
Both cases use NorthWestern or Montana-Dakota rules: 1-for-1 kWh credits and a yearly reset. Our cases assume 40% of the power is used at home as it is made and 60% is sent out.
| Case, NorthWestern or Montana-Dakota | Year-one value | After upkeep | Simple payback |
|---|---|---|---|
| All banked credits used before the reset | $1,390 | $1,176 | 16.6 years |
| Half the exported credits lost at the reset | $973 | $759 | 25.6 years |
Swipe the table sideways to see every column.
Montana’s net metering law covers the two regulated utilities, about 6 in 10 Montana homes. Electric co-ops are owned by their members and write their own solar rules.
About 59% of Montana homes. Reset in January, April, July or October, your pick. $200 application fee, not refunded.
Next: tell your installer the reset month to enter.
About 3.5% of Montana homes. Rate 92 has the same 50 kW limit, carry-forward and yearly reset as the state law.
Next: ask for its application and pick your reset date.
Montana Code 69-8-605 leaves co-ops out of the state law. Flathead Electric alone serves about 11% of Montana homes.
Next: get the co-op’s net metering terms in writing before any design work.
| Utility | Share of Montana homes | Extra power | Yearly reset |
|---|---|---|---|
| NorthWestern Energy | about 59% | 1 kWh for 1 kWh | A month you pick |
| Montana-Dakota Utilities | about 3.5% | 1 kWh for 1 kWh | A date you pick |
| Flathead Electric Co-op | about 11% | Banked as kWh credits | Not stated in its bill guide |
| Yellowstone Valley Electric | about 4% | Banked up to 12 months | Set by the co-op |
| Other co-ops, Mission Valley Power | The rest | Set by each utility | Set by each utility |
Swipe the table sideways to see every column.
Yellowstone Valley charges net metered accounts for demand, a fee based on the most power your home draws at one moment. At Flathead Electric, credits do not lower the basic charge or the demand charge. Shares are our calculation from federal data for 2024 (EIA Form 861, 557,434 Montana homes).
A credit is a kWh, so it is worth whatever a kWh costs when you use it. NorthWestern’s supply price fell on October 1, 2026, cutting a bill for a home that uses 750 kWh a month by $8.57, or 6.58%. The next change is due January 1, 2027.
NorthWestern asked to change how solar homes are billed, and the regulator said no. A later change is possible, but only for systems connected after it.
The Public Service Commission rejected NorthWestern’s net metering plan and a new rate class for solar homes.
The estimated monthly bill increase for new solar homes from the demand charge NorthWestern proposed.
The commission may approve a separate class after a rate case. It covers only systems connected on or after that order.
The most a net metered system can be under Montana law.
NorthWestern’s rules showed no separate solar rate when we checked on September 30, 2026. Homes connected before any new order keep the current rule unless they choose to switch.
11th lowest of 51 and below every neighbor: South Dakota $2.85, Idaho $2.96, Wyoming $3.14, North Dakota $3.39. These are modeled cash prices, not quotes we collected.
| Size | Cash at $2.73 per watt | Power made a year |
|---|---|---|
| 5 kW | $13,650 | 7,043 kWh |
| 7.13 kW (typical) | $19,465 | 10,043 kWh |
| 8 kW | $21,840 | 11,269 kWh |
| 10 kW | $27,300 | 14,086 kWh |
No rebate and no tax credit. The bill credit is the main benefit. Two state programs help, and both need an application.
Of system value, for 10 years. Send Form AB-14 to your Department of Revenue field office by March 1.
Fixed, up to $40,000 for up to 10 years. 4.023% APR with closing costs, by DEQ’s own example.
Montana’s credit for home energy systems was repealed in 2021.
Not for a system you own placed in service after December 31, 2025.
| How you pay | Panels owned by | Ask before you sign in Montana |
|---|---|---|
| Cash | You | The reset month on the utility form, and a size based on your bills |
| DEQ loan | You | Apply before work starts: October 1 to 30, 2026 now, then January 1 to 29, 2027 |
| Bank or installer loan | You | Cash vs. financed price; a dealer fee adds years |
| Lease or PPA | The company | Whether one is offered here, and who picks the reset month |
Swipe the table sideways to see every column.
Two companies that list Montana service, A to Z, not ranked. Facts from their own sites, read October 13 and 14, 2026. Neither prints a Montana license number, so ask for it.
Neither company buys homeowner leads from EcoGen America. How we make money. Purelight Power, which listed Montana service, shut down in December 2025, so it is not here.
Ask each installer which reset month it will file, and to size the system from a year of your bills.
Get Montana quotes sized to your billsEcoGen America does not sell or install solar. When you request quotes, we pass your request to solar providers serving your area, and they pay us for the introduction. Providers can include installers, solar marketplaces and lead exchanges, and more than one may contact you. You never pay us. Privacy policy
CEO of EcoGen America. Since 2021 he has connected homeowners with residential solar installers in all 50 states.
About Dean
Founder of EcoGen America. He has worked in residential solar since 2016 and maintains the EcoGen Solar Cost Index.
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