What a Madison roof produces in a year
The planning figure for Madison is about 1,244 kWh a year for every kW of panels installed. It is a derived estimate rather than a published municipal statistic: a standard performance ratio applied to satellite irradiance data for the area. Use it to work out whether the idea is worth pursuing, and let a site survey produce the number that goes into a contract.
Four things move that number on a given house. Orientation sets the daily shape, with south-facing planes generating across the whole day and east or west faces weighted to one end of it. Pitch affects output and how fast snow clears. Usable area, once vents, chimneys and setbacks are excluded, caps the system size. And shading decides how much of the theoretical output the array actually collects, particularly in winter when the sun is low and reaches under tree canopies that look harmless in July.
Ask for modelled production plane by plane rather than as a single house total. Panels put on a compromised face still raise the headline figure while returning less per dollar, and the breakdown is what lets you compare two proposals as though they were the same product.
Madison Gas and Electric, and connecting to the grid
Madison Gas and Electric, MGE, is the electric utility for Madison. Its solar page directs customers considering their own system to its Connect to Our Grid interconnection steps, which is the process your installer follows to get the array approved for connection and correctly metered.
Treat that as a separate approval from the city permit, because the two run on their own timetables. A project can be permitted and still waiting on the utility, or cleared by the utility and waiting on an inspection. When you ask where a job stands, ask which of the two is outstanding rather than accepting a single switch-on date.
It is worth seeing the interconnection submission before it is filed. The application defines the system that gets connected, so a change to the array size after approval means going back to the utility, and that is avoidable rework.
How Wisconsin credits the power you send back
Wisconsin requires its investor-owned utilities to offer net metering under Public Service Commission rules. Excess energy your panels send to the grid is credited against the power you draw at other times, typically at the retail rate. That is a straightforward arrangement to model, and it is why sizing here is mostly a question of matching your annual consumption.
The detail is that each utility administers its own tariff under PSC oversight. We Energies, Madison Gas and Electric, Alliant Energy Wisconsin, Wisconsin Public Service and Xcel Energy in northern Wisconsin each run their own schedule, so the terms that matter to you are MGE terms specifically, not a statewide average.
Ask your installer to confirm the current MGE net metering schedule for your rate class before the system size is fixed, and to size the array against twelve months of your own usage rather than against the roof area available. Because the credit is applied against the power you draw at other times, a system generating well beyond what your household consumes runs out of consumption to offset.
Permits: an appointment, not a walk-in
Madison's Building Inspection division reviews residential building permits, solar included, by appointment only, at 215 Martin Luther King Jr Blvd. That single detail changes how a project is scheduled, because the filing step has to be booked rather than fitted in around other work.
The division does not publish a solar-specific review turnaround. Rather than guessing at one, ask your contractor what recent Madison jobs have taken and what the submission package needs to contain. A contractor who works in the city regularly will answer from experience; one who does not should say so plainly.
Ask as well who is booking the appointment and attending it. Where a homeowner assumes the contractor is handling a step and the contractor assumes the same of the homeowner, the result is a project that has not actually started.
If you do not have a roof of your own
Single-family detached homes are 39.9 percent of the 133,530 housing units in Madison. Those owners control their own roof and can run the whole sequence themselves: design, permit appointment, MGE interconnection, inspection.
A further 28.7 percent of units sit in buildings of 20 or more units, a large share driven by the university-area rental market. Solar on those buildings needs building-owner sign-off, and the array normally offsets a building account rather than any individual apartment. Small multifamily forms of two to four units make up 10.7 percent of the stock combined, and those raise a metering question first: an array feeds one electrical service, so which meter it connects to decides whose bill it reduces.
For anyone in the second and third groups, MGE separately offers a Shared Solar community solar program. That is the route worth investigating if you cannot install on your own roof, whether because you rent, because a board controls the building, or because the roof itself is shaded or unsuitable. It is a different product from a rooftop system, so ask MGE directly what participation involves before comparing it with an installer quote.
Focus on Energy, and the January 2027 deadline
Focus on Energy is Wisconsin's statewide program, and it currently pays a cash rebate of $600 per kW installed, up to $2,400, for qualifying systems. Because the reward is per kW with a cap, the incentive stops growing once the system passes 4 kW, so it does not scale with a larger array and should not be treated as a fixed percentage of project cost.
The application timing is strict: applications are due within 60 days of completion, and no later than January 31, 2027. Sixty days after your system is finished is not a long window, so agree in writing who is submitting the application, you or the contractor, and put a reminder in your own calendar rather than relying on the installer to remember.
Eligibility also requires using a participating contractor and connecting to a participating utility, so confirm both before you count on the money rather than after the panels are on the roof. Rewards are updated periodically, which is another reason to check the current amount on the Focus on Energy website at the point you are quoted rather than relying on a figure someone quoted last year.
The federal credit is not part of a 2026 purchase
The 30 percent federal residential tax credit under Section 25D applied through December 31, 2025 and is not available for a purchased home system placed in service after that date. That means a 2026 purchase in Madison cannot claim it, and any payback calculation, quote or online calculator that still includes it is describing an earlier year.
That is a material change, because the credit was large enough to carry a substantial part of a residential project. Removing it changes the arithmetic on system size, on whether a battery is worth adding, and on how long the payback runs. Ask any installer to show you the numbers without it.
If you go solar through a lease or a power purchase agreement instead of buying, the provider may still claim the business version of the credit and pass part of the value through in the rate you are offered. That is a question to put to the provider directly, and to check with a tax advisor, rather than an assumption to build into your own budget.