Montana Solar Calculator 2026
Montana's net metering protection is legally anchored and more secure than in many states — but the annual settle-up mechanic is unique and can cost you money if you don't plan around it. Get a personalized savings estimate below, then read the details that matter specifically to Montana.
Estimate Your Solar Savings
Find out how much you can save based on your location and current energy usage.
What Montana Solar Owners Need to Know in 2026
Federal Tax Credit Expired — Do Not Factor It In
The 30% federal residential solar tax credit (Section 25D) expired December 31, 2025 under the One Big Beautiful Bill Act. It does not apply to any system installed in 2026 or later. Any installer or sales material that still references the 30% federal credit for a 2026 installation is incorrect.
Net Metering: Legally Protected at Full Retail Rate
Montana law requires NorthWestern Energy to offer full retail-rate net metering for residential systems up to 50 kW. The Montana Public Service Commission rejected NorthWestern's attempt to eliminate net metering and create a separate solar rate class — a significant win for solar owners.
Net metering must continue by law until rooftop solar reaches 5% of NorthWestern's peak load. As of 2026, penetration is only around 1%, so this protection is not at risk in the near term.
The Annual Settle-Up: Montana's Distinctive — and Costly — Mechanic
Montana's net metering includes an annual settle-up that works differently from most states. Monthly excess generation credits roll over throughout the year. But at your chosen settle-up date — you pick January, April, July, or October — any remaining unused kWh credits are forfeited entirely to NorthWestern Energy with zero compensation. No avoided-cost payout, no cash — nothing.
This makes two things genuinely important:
- System sizing: Over-sizing means you'll routinely carry credits into your settle-up date and forfeit them. Size close to your actual annual consumption.
- Settle-up month choice: Consider choosing April — you'll have banked production from spring, summer, and fall to draw down before the settle-up, and you're entering your main production season with a fresh slate. January means forfeiting credits right when winter production is at its lowest and bills tend to be higher.
Confirm current settle-up options directly with NorthWestern Energy — terms can change.
Electricity Rates in Montana
Montana's average residential electricity rate is roughly 12–14 cents/kWh, well below the national average of ~18.8 cents/kWh. Lower rates mean longer payback periods compared to high-cost states.
Flathead Electric has historically been among the cheapest in the state at around 9.7 cents/kWh — extending payback periods further for those customers. Verify your current rate on your utility bill.
Sun Exposure
Montana averages roughly 4.5 peak sun hours/day — solid for a northern state. Eastern Montana (High Plains) tends to be sunnier than western Montana, where Pacific weather systems bring more cloud cover.
Your installer should provide a site-specific production estimate rather than relying on statewide averages.
Montana-Specific Solar Incentives
State Income Tax Credit
Montana offers a state income tax credit for a "recognized nonfossil form of energy generation" installed at a primary residence. Sources conflict on the current exact dollar cap — some cite up to $500 per individual or $1,000 per household, others cite different figures. Do not rely on any single published number. Contact the Montana Department of Revenue for the current credit amount and eligibility rules. Unused credit can generally be carried forward for a few years if it exceeds your tax liability in the installation year.
No State Sales Tax
Montana has no state sales tax at all. Solar equipment — panels, inverters, racking, wiring — is purchased entirely free of sales tax. No special exemption application is required. This is a permanent, inherent advantage of buying in Montana.
Property Tax Exemption (10 Years)
Montana exempts a portion of solar equipment assessed value from property taxes — historically up to $20,000 of assessed value for a single-family residence — for 10 years after installation. This is time-limited, not permanent; property taxes may adjust after the 10-year period. Confirm the current cap with your county assessor's office and ask about the filing process to claim the exemption.
AERLP Low-Interest Financing
Montana DEQ's Alternative Energy Revolving Loan Program (AERLP) offers low-interest financing for qualifying households pursuing solar and other renewable energy projects. Funding availability and loan terms vary from year to year. Check directly with Montana DEQ to see whether the program is currently funded and accepting applications.
If You're Served by a Rural Electric Cooperative
Rural electric cooperatives — including Flathead Electric Cooperative and Yellowstone Valley Electric — also offer net metering programs in Montana, but each cooperative operates independently and sets its own rates, rules, and procedures. Do not assume NorthWestern Energy's tariff terms or the annual settle-up mechanics apply to your cooperative. Contact your specific co-op directly for their current net metering policy before purchasing a system.
Frequently Asked Questions
Everything you need to know about solar incentives, costs, and savings.