Solar Calc

Solar Panel Cost in St. Louis, MO (2026 Estimate)

ByIndependent solar research and calculators

Data last updated

St. Louis averages about 4.8 peak sun hours a day (about average for the US, a little sunnier than the Missouri average of 4.5), and pairs with Missouri's approximate residential rate near 12ยข/kWh. In the model used here, an 8 kW system produces roughly 11,210 kWh a year and trims about $1,300 off annual electricity costs, paying back its net cost in about 12.5 years (versus 13.3 years for Missouri as a whole). Local shading, roof, and your utility's export terms move the real figure.

Estimated system cost and payback in St. Louis

Costs assume roughly $3.00/watt installed; the net column applies a 30% federal credit for comparison with quotes that include it. Savings use St. Louis's sun hours and Missouri's rate.

Modeled solar cost, production, savings and payback in St. Louis by system size
System size Gross cost Net after 30% credit Yearly production Yearly savings Payback
6 kW $18,000 $12,600 8,410 kWh $1,000 12.5 yrs
8 kW $24,000 $16,800 11,210 kWh $1,300 12.5 yrs
10 kW $30,000 $21,000 14,020 kWh $1,700 12.5 yrs

The 30% federal Residential Clean Energy Credit ended for systems paid for after December 31, 2025 under the 2025 federal budget law. Net-after-credit figures apply only if you still qualify (for example a 2025 expenditure, or a leased system where the installer passes a credit through). Confirm with a tax professional.

Net metering and utilities around St. Louis

Under the Missouri Easy Connection Act, every electric utility must offer net metering for systems up to 100 kW, and residential exports are credited at the retail energy rate. Any surplus in a month becomes a kilowatt-hour credit applied to the next bill, and the credits keep rolling forward through a 12-month cycle. Whatever remains unused at the end of that cycle is forfeited to the utility with no payment, so a system sized above annual consumption gives away its extra output.

Ameren Missouri serves St. Louis and eastern Missouri, Evergy covers Kansas City and the western counties, and Liberty (formerly Empire District) supplies the southwest around Joplin, with municipal utilities and about 40 rural cooperatives handling the rest. Residential rates are among the lower ones in the Midwest, roughly in the low-to-mid teens of cents per kilowatt-hour, which lengthens payback relative to coastal states but has been rising steadily. Both investor-owned utilities have introduced optional time-of-use plans; on the standard flat rate a south-facing roof and full-retail net metering keep the math simple.

For the full state picture, including incentives, property and sales tax treatment and the complete net metering notes, see the Missouri solar cost page.

Other Missouri cities

Sources and methodology

Every figure on this page is computed from two published inputs (average peak sun hours and the state's average residential electricity rate) plus the documented assumptions on the methodology page. It is a transparent model, not a survey of installer quotes. Inputs last reviewed .