Montana has solid residential solar rules — full 1:1 retail net metering, a 10-year property tax exemption, no statewide sales tax to apply to equipment. The rules aren't the problem. The problem is the price of electricity.
At about ~12¢/kWh residential, Montana has among the lowest retail rates in our verified set — well below the US average. At 1:1 net metering every kWh of solar you produce is worth roughly your retail rate, and in Montana that's not very much. Our model puts typical payback near ~17.7 years.
That makes Montana a clarifying case. Massachusetts has the same 1:1 retail net metering rule at ~30¢/kWh and our model puts MA payback near ~7 years. Same mechanism, very different math. Net metering doesn't make solar pay off on its own — it makes solar pay off when paired with expensive grid electricity. Montana's electricity isn't expensive.
Two other things have to clear before the payback number makes sense. The federal credit is gone, and Montana does not have a state income tax credit despite a lot of stale online coverage claiming a "$1,000 Montana credit."
What changed
The federal Residential Clean Energy Credit (§25D) — the 30% homeowner credit — was repealed for systems installed after December 31, 2025. For 2026 Montana buyers, the federal credit on a purchased system is $0. The same applies to home batteries purchased outright. The §48E commercial credit (30%) still exists, but only for leased or third-party-owned systems — the lessor claims it, not you. Full federal context here.
VERIFIED 2026-06 · irs.govNet metering: 1:1 retail, with annual settle-up
Montana's PSC requires NorthWestern Energy (the dominant residential utility, modeled here) and Montana-Dakota Utilities to offer full retail 1:1 net metering for residential systems up to 50 kW.
- Self-consumed solar offsets your full retail rate (~12¢/kWh).
- Exports are credited at the same retail rate, 1:1.
- Credits roll over month-to-month.
- This calculator models the NorthWestern Energy case.
Important: Montana uses an annual settle-up. Any remaining excess credit resets to zero at your settle-up month — credits do not bank indefinitely the way they do in Alaska or in New Mexico (PNM). If you over-produce on an annual basis, the surplus is effectively given back to the utility at zero value. Don't oversize beyond your annual consumption.
Worth knowing: NorthWestern Energy attempted to end Montana net metering in 2019. The Montana PSC rejected the attempt. The 1:1 rule is currently stable, but it has been challenged before, and it could be challenged again. Rural electric cooperatives outside NorthWestern and MDU territory set their own policies independently and may not offer full retail — verify with your specific co-op if you're outside the IOU footprint.
VERIFIED 2026-06 · Montana PSC net metering; NorthWestern Energy tariffThe driver: ~12¢/kWh retail
Montana residential electricity averages about ~12¢/kWh on NorthWestern, below the US average. That's the single biggest reason Montana solar payback runs longer than higher-rate 1:1 states like Massachusetts (~30¢, payback ~7 years) or New Jersey (~26¢, payback ~6.5 years).
Under 1:1 net metering, that retail rate is the value of every kWh your system produces. The math is straightforward: when each avoided kWh saves you ~12¢ instead of ~30¢, payback stretches by roughly the same factor. That isn't a Montana-specific failure; it's just arithmetic.
Rates are rising. Higher future retail makes future self-consumption more valuable, which helps the lifetime value of a Montana system. But the headline payback number reflects today's rates.
VERIFIED 2026-06 · eia.govNo state income tax credit — APEC was repealed
This is the single biggest source of stale Montana solar quotes online.
Montana had an Alternative Energy Production Credit (Form APEC) — up to $1,000 for residential renewable installations. The 2021 Montana Legislature repealed it. It cannot be claimed after Tax Year 2021. There is no replacement credit.
If you see a 2024-or-earlier Montana solar guide or contractor quote that includes "$1,000 Montana solar credit" or anything like it, the math is out of date. Discount it.
VERIFIED 2026-06 · Montana DOR — APEC repealed 2021What Montana does have: no sales tax, 10-year property exemption
No statewide sales tax. Montana has no general sales tax, so there is no sales tax to apply to solar equipment. (Some local-option resort tax districts exist — they generally don't apply to home-equipment purchases like solar, but verify if you're in one.)
10-year property tax exemption. Montana exempts the added home value from solar from property tax for 10 years under Form AB-14. That's a real benefit during the first decade. After year 10, the added value becomes assessable for property tax purposes — worth budgeting for if you're planning to stay in the home long-term.
Battery in Montana — weak twice over
A home battery makes economic sense when the retail-export gap is large — you store solar that would have exported cheaply and use it instead of buying retail later. Under Montana's 1:1 net metering, that gap is effectively zero, like Florida, Virginia, New Mexico, Colorado, Massachusetts, New Jersey, New York legacy, and Maryland. On pure energy arbitrage, a battery in MT doesn't pay off.
Montana is also weakened on the resilience side. The economic value of resilience comes from avoiding expensive grid power during outages. In Montana, the grid kWh you're avoiding is ~12¢, not 30¢ or 40¢. An hour of outage backup is worth less here than it is in MA or HI. The case isn't gone — winter storms and rural outages are real — but it's smaller per outage hour.
There's no federal credit on the battery purchase in 2026 (§25D repealed for storage purchase), and Montana has no state battery incentive. If you want a battery in MT, the case is specific outage hardening for your situation, not payback math.
The honest picture
Montana solar in 2026:
- Federal credit: $0. Not 30%. Discount any quote that still cites federal.
- No state income tax credit. APEC was repealed by the 2021 Legislature — cannot be claimed after Tax Year 2021. Discount any quote citing a "$1,000 Montana solar credit."
- Net metering: full retail 1:1 on NorthWestern Energy and MDU, up to 50 kW. Annual settle-up resets excess credit to zero — don't oversize. Rural co-ops set their own policies.
- NorthWestern tried to end net metering in 2019; PSC rejected. Currently stable but has been challenged.
- Retail rate: ~12¢/kWh on NorthWestern, rising — but still below the US average.
- Sales tax: no statewide sales tax.
- Property tax: 10-year exemption on added value (Form AB-14). Becomes assessable after year 10.
- Battery: weak on arbitrage (1:1 gap is ~0) and weak on resilience economics (low retail means each avoided outage kWh is worth less). No state battery incentive.
- Typical payback: ~17.7 years.
Montana isn't a bad state for solar in terms of rules — the net metering rule is one of the better ones in the country, and the absence of sales tax helps. It's a state where the economics are dictated by retail rates, not policy. Cheap electricity is good for consumers in general, but it makes solar payback long because the savings per kWh are small. That's an honest result, not a failure of the rules.
If you're set on solar in Montana, three things shape whether the numbers work for you: how much you use the production directly (self-consumption matters more than export under any net metering rule), what your future rate trajectory looks like (NorthWestern rates rising helps lifetime value), and how long you stay in the home (after year 10, the property tax exemption ends — if you sell before then, you captured the full benefit; if you stay decades, you'll pay property tax on the added value eventually).
Before you commit:
- Reject any quote that includes a 30% federal credit or a "$1,000 Montana state credit." Both are gone. Federal repealed end-2025; APEC repealed 2021.
- Confirm whether you're on NorthWestern Energy, MDU, or a rural co-op — only IOUs are required to offer the 1:1 rule. Co-ops may not.
- Don't oversize. Montana's annual settle-up means surplus is given back at zero value — size to your actual annual consumption.
- Plan around the 10-year property tax exemption ending — if you intend to sell within 10 years, you keep the benefit; if you stay longer, factor in the eventual assessment.
- Don't model a battery as a payback shortener in Montana. The case is specific outage hardening.
- Run the calculator with your actual ZIP and system size.
Estimates only — net metering applies to NorthWestern / MDU; rural co-ops differ. Verify with your utility. This is not financial advice.