Montana Solar Guide 2026
Everything Montana homeowners need to know: costs, incentives, net metering policy, and what makes this state unique for solar.
Reviewed by Marcus Vance · Planning data requires verification against your utility and state program source.
Policy dataset review cadence: every 45 days · next review 2026-09-07 · program effective dates and expiration rules must be confirmed in the linked source.
Quick answer
Montana solar economics depend on your roof, utility and quote. This page uses illustrative assumptions of 4.8 peak sun hours, $2.95/W and 11.0 cents/kWh; these are not verified current market averages or account rates.
Notes updated 2026-07-24
- Best for
- Montana homeowners comparing solar costs, incentives, and payback assumptions.
- Inputs needed
- annual kWh usage, utility rate, installed $/W, net-metering policy
- Formula used
- Planning production = system kW x peak sun hours x 365 x (1 - 14.08% losses). Retail-value ceiling = production x assumed retail price; actual export value can be lower.
- Method references
- state incentive data, utility tariff checks, Wattcrunch price benchmarks
Key fact about Montana solar
Montana has solid sun hours (especially eastern MT) and full retail net metering, but a tiny state income tax credit and low electricity rates limit solar ROI. Billings and Missoula are the main solar markets.
Peak sun hours
4.8
hrs/day planning assumption
Illustrative energy rate
11.0¢
per kWh
Illustrative install cost
$2.95/W
before incentives
Illustrative 8 kW system in Montana
Annual production
12,043 kWh
Retail-value ceiling, not savings
$1,325
System cost (est.)
$23,600
Includes 14.08% planning losses. Valuing all production at retail is a ceiling, not a net-billing savings estimate; actual self-use, export rates and ownership costs change the result. No new Section 25D homeowner credit in 2026.
Worked example
Montana: a transparent 8 kW planning example
This example shows how the published Montana assumptions flow through a simple first-pass calculation.
Example household usage
10,800 kWh/year
Estimated production
12,043 kWh/year
Rate used in the example
11.0 cents/kWh
Retail-value ceiling, not bill savings
$1,325/year before ownership costs
Montana Net Metering Policy
Full retail net metering (MCA 69-8-601)
Montana law requires full retail net metering for systems up to 50 kW. NorthWestern Energy and other utilities must credit exports at retail. Annual settlement with unused credits.
Montana Solar Incentives
Programs require eligibility checks and cannot always be combined. Federal 25D credit is $0 for new homeowner-owned systems in 2026.
- ✓State income tax credit: 5% of cost (up to $500)
- ✓Property tax exemption
Top Utilities in Montana
Interconnection timeline: 4–8 weeks
State-specific decision guide
What to verify before signing a Montana solar quote
In Montana, the financial result depends on more than sunshine or the headline installation price. Confirm the export rule, program eligibility date, and interconnection timeline for your exact utility before treating a payback estimate as a promise.
Export value
This page models full retail net metering (mca 69-8-601). Ask which tariff and export credit apply to your account, not only which program name appears in the proposal.
Incentive eligibility
Check equipment, income, installer, application, and placed-in-service rules before subtracting an incentive from the quote. Programs can close or change terms.
Interconnection
Budget for the published 4–8 weeks and confirm who pays for a required meter, service upgrade, or engineering review.
Source trail: production assumptions use NREL PVWatts; incentive discovery should be checked against DSIRE; electricity-market context is available from the EIA. Confirm final tax treatment with the IRS and your utility.
Calculate your Montana solar economics
Savings links carry illustrative planning inputs. Replace them with your actual tariff and quote; sizing still needs your usage and production assumptions.
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