Production, and what the roof has to give you
Plan around roughly 1,262 kWh a year for every kW installed. That number is derived rather than published for the city: it applies a standard performance ratio to satellite irradiance data for the area, which makes it a sound basis for a first estimate and no substitute for a survey of your own roof.
The variables that move it are the same on every house and different on each one: which way the main planes face, how steeply they pitch, how much clear area is left once vents, chimneys and plumbing stacks are worked around, and what shades the roof through the year. In the older neighbourhoods, mature street and yard trees are usually the binding constraint, and the honest test is a shading model for the low winter sun rather than a photograph taken in June.
Roof age deserves a decision of its own before anything is ordered. Panels last for decades, and taking an array down and putting it back so shingles can be replaced underneath is money spent twice. If the roof is close to needing work, doing both together is normally the cheaper order of operations.
Xcel, kilowatt-hour credits, and the annual reset
Saint Paul's own city news confirms Xcel Energy as the electric utility here, and Xcel is the counterparty for both your interconnection application and your net metering arrangement.
Minnesota requires electric utilities to offer net metering under Minn. Stat. 216B.164. Excess generation is credited as kilowatt-hour credits on your bill and carries forward month to month, resetting annually. Residential eligibility at an investor-owned utility runs up to 1,000 kW, well beyond any house, and utilities may not impose standby charges on qualifying systems of 100 kW or less without approval from the Public Utilities Commission.
The annual reset is the design constraint. Credits banked in the long summer days are what carry you through the short winter ones, which is exactly what the carry-forward is for. But a system sized well beyond your yearly consumption builds a surplus that the reset removes, so the extra panels are working for nothing. Under the statute a qualifying facility under 40 kW connected to a public utility such as Xcel may elect compensation at the average retail utility energy rate for net excess generation. That is an election the customer makes, so ask which option the quote assumes and what it implies at the reset.
Who owns the roof in Saint Paul
Single-family detached homes are 48.5 percent of the 133,051 housing units in Saint Paul. For those households the process is contained: a design, a city permit, an interconnection application to Xcel, an inspection, and a commissioning. No third party has to agree.
Buildings of 20 or more units hold 25.3 percent of the stock, and there the roof belongs to the building. A project needs building-owner sign-off, and the array normally offsets a building account rather than any individual apartment, which makes it a capital decision rather than a household one. If you rent or own in such a building, the first useful question is who controls the roof and whether an assessment has ever been done.
Duplexes are 6.3 percent of the stock and are concentrated in the older neighbourhoods. A duplex usually carries more than one electrical service, and an array offsets only the service it is wired to. Settle which meter the system feeds, and whose bill that is, before a design is drawn.
The cheap step before the expensive one
Saint Paul and Xcel Energy run a Home Energy Squad program together, offering free visits to qualifying residents. That kind of visit is aimed at the building rather than at generation: air sealing, insulation, and the equipment that quietly drives a winter bill.
Doing that first is not a delay tactic. Solar is sized against your consumption, so every kilowatt-hour you stop wasting is a kilowatt-hour of panels you do not have to buy. In a city with a lot of older housing stock, the efficiency work often costs a fraction of the array it displaces.
It also sharpens the quote. Twelve months of post-efficiency usage data is a better basis for sizing than a historical bill that reflects a house you have since improved, and it makes the comparison between two installer proposals a comparison of the same thing.
Where the tax position stands
Minnesota exempts qualifying solar equipment from state sales and use tax under Minn. Stat. 297A.67, Subd. 29, which takes the 6.875 percent state sales tax off the equipment in a qualifying system as defined in Minn. Stat. 216C.06. Your installer confirms which components qualify, and because the exemption applies at purchase it is already reflected in a correctly prepared quote rather than claimed back later.
Residential solar energy generating systems are exempt from Minnesota property tax under Minn. Stat. 272.02, Subd. 24. Installing an array does not increase the assessed value of your home for property tax purposes, so the annual property tax bill is unaffected.
The federal residential credit no longer applies to purchasers. The 30 percent credit under Section 25D applied through December 31, 2025 and is not available for a purchased home system placed in service after that date, so it should not appear in a 2026 quote or in any payback calculation attached to one. Under a lease or a power purchase agreement, the provider may claim the business version of the credit and pass part of the value through in your rate, which is worth asking the provider to spell out and worth checking with a tax advisor.