Verify any rebate with the utility, not the installer
Missouri investor-owned utilities historically ran solar rebate programmes, but these have largely been discontinued. Published guides and older sales material still reference them, which is how a stale figure ends up in a current quote.
So if a rebate appears in your quote, confirm directly with your own utility whether it is currently open, what it pays and whether funding remains. That is a short call and it settles the question definitively.
Ask the installer where their rebate figure came from and when they last confirmed it. An installer working Missouri actively will know the current position without having to check.
Then ask to see the whole projection with the rebate removed. If the project only works with it, you have learned something important about how much margin the case actually has.
The other two assumptions worth removing
Ask whether the projection applies the 30 percent federal Residential Clean Energy Credit. It expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit, and a quote that still applies it is overstating your return substantially.
Ask whether it assumes a property tax exemption. The Missouri Supreme Court held on August 9, 2022 in Johnson v. Springfield Solar 1, LLC that the exemption under Section 137.100(10) is unconstitutional, and the State Tax Commission has since issued guidance to assessors.
Between those two and a discontinued rebate, a projection copied from an older template can be wrong in three places at once. That is not usually dishonesty, it is staleness, but the effect on your decision is the same.
Ask your installer to rebuild the arithmetic from what still exists: net metering under the Easy Connection Act and the electricity you stop buying. If a salesperson resists producing that version, the resistance is itself informative.
What the remaining arithmetic looks like
Missouri's Net Metering and Easy Connection Act covers qualified net metering units of 100 kW or less and applies to regulated utilities, municipal electric utilities and rural electric cooperatives alike, all required to adopt policies establishing a simple interconnection and net metering contract.
Standard residential tariffs apply a retail-rate offset for in-period consumption, with year-end surplus reconciled at avoided cost. So build to your consumption rather than beyond it, and ask what percentage of your annual usage the proposed system covers.
Ask for the design to be built from your last twelve months of electricity bills rather than a generic household profile, and ask to see the calculation. That is the most effective way to compare two quotes on the same basis.
For a system of ten kilowatts or less the utility must review and respond within 30 days of receipt, and within 90 days for larger systems up to 100 kilowatts. Ask the date the complete application was submitted so you know when a response is due.
Building the number from confirmed pieces only
Three things people expect in Missouri are either gone or unreliable, and a quote built on any of them overstates your return. The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit.
Utility solar rebates historically existed here but have largely been discontinued. If a rebate appears in a quote, confirm directly with your own utility whether it is currently open, what it pays and whether funding remains, before you sign anything.
And the property tax exemption most guides still list was held unconstitutional by the Missouri Supreme Court on August 9, 2022. Ask your county assessor how residential solar is being assessed at your address rather than assuming an exemption applies.
What does exist is net metering under the Easy Connection Act and the electricity you stop buying. Ask any installer to rebuild the arithmetic from those two things alone, and treat resistance to producing that version as informative in itself.