Snow is a real line in the model
Iowa winters bring genuine snow cover, and snow on an array produces no electricity at all until it clears. The size of the loss depends on how much snow falls, how long it stays, and how readily the array sheds it.
Panel tilt and orientation drive the shedding. A steeper tilt sheds more readily and also shifts production toward the shoulder seasons, which is often a better trade in a northern climate than maximising a summer peak.
Ask what snow allowance the production model applied and how it was derived. A model built from generic irradiance with no snow adjustment is describing a milder place.
Ask about the mounting too, and specifically whether shed snow would land somewhere it causes a problem, such as over a walkway or an entrance. That is easier to solve at design stage than afterwards.
The seasonal profile under inflow-outflow
Iowa uses inflow-outflow billing, so electricity you consume as it is generated avoids inflow entirely while the rest becomes outflow credited under the tariff, with credits carrying forward.
A northern seasonal profile means heavy summer generation and light winter generation, while a household with electric heating may see the reverse in consumption. The carry-forward is what bridges that.
So ask for the estimate month by month rather than as an annual total, with the credit balance tracked. An annual figure conceals whether the design actually matches your household through the year.
Ask also what happens to outflow credits over time under your utility tariff, and whether there is any point at which they are forfeited or cashed out.
The rest of the estimate worth checking
Ask what data source the annual production figure came from and whether it applies location-specific irradiance for your address rather than a regional average.
Ask what shading analysis was done and what it assumed about tree growth over twenty-five years. A model built on today canopy will overstate a mature lot in ten years.
Ask what soiling and annual degradation assumptions it used. Panels lose a small amount of output each year, and a model holding production flat across the term overstates the back half of the projection.
Then ask for the figure in kilowatt hours per year rather than in dollars, so the production assumption and the rate assumption can be checked separately rather than as one number.
The pieces to separate in a projection
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, and the Iowa solar tax credit expired for residential installations completed after December 31, 2021.
Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask what a provider claims and what reaches you in the rate.
What exists is the sales tax exemption, the five-year property tax exemption, avoided inflow at your retail rate, and outflow credits under your utility tariff, subject to the value of solar review ahead.
Ask for the projection built on a monthly production profile with a stated snow allowance, your own rate from a recent bill, and fixed charges included.