Most Ann Arbor homes are not detached houses
Of the 54,399 housing units in Ann Arbor, 41.6 percent are single-detached. That is a lower share than most Michigan cities and it changes what advice is useful. Buildings of 20 or more units hold 14.9 percent, buildings of 5 to 9 units hold 14.4 percent, and buildings of 10 to 19 units hold a further 7.7 percent. In each of those the roof belongs to the building owner.
For a resident of one of those buildings, an individual installation is not on the table, and an array on the building normally offsets a building account rather than any single apartment. That is not a reason to drop the subject, but it does change who you are talking to: the realistic route is asking the owner or the management company whether they have looked at it, and what would make it worth their while.
Single-attached row houses and townhouse-style units are 12.3 percent. Those often sit somewhere between the two cases, with a roof plane that may be yours and a structure shared with the neighbour, so the first step is establishing what you actually own. That is a survey question and sometimes a title question, and it is worth answering before you collect quotes.
If you do control a roof
The planning figure is about 1,197 kWh a year for every kW of panels. It is derived from satellite irradiance with a standard performance ratio applied rather than measured locally, so use it to judge whether to proceed and let the site survey produce the number that belongs in a contract.
Shade deserves particular attention in this city. Established neighbourhoods with mature canopy are exactly the conditions in which an annual average misleads: a tree that clears the roof in July can cut straight across it in the low winter sun, when the array is producing least and the loss hurts most. Ask what shading data the model uses and whether it accounts for the winter sun angle.
Beyond shade, the usual four apply. Orientation sets the daily shape of output, pitch affects yield and snow clearance, and usable area is smaller than the roof looks once vents, stacks and setbacks come out. A quote should show all of it per roof plane, not as a single house figure.
DTE Rider 18 and the price of an exported kilowatt-hour
Michigan replaced traditional net metering with a Distributed Generation program, and DTE administers its version as Rider 18, open to systems up to 550 kW. Power you draw is billed at the retail rate of the schedule Rider 18 attaches to. Power you export is valued at the power supply component of that rate, including Power Supply Cost Recovery.
So the two directions are not symmetric, and the asymmetry is the design constraint. A kilowatt-hour you consume as you generate it is worth the full retail rate you avoided paying. The same kilowatt-hour sent to the grid earns the narrower supply-based credit. The credit does offset all electric charges at the premise except securitization charges, which is broader than energy-only crediting, and unused credit carries forward in an Excess Generation Bank.
For a household this argues for two things: sizing to consumption rather than to roof area, and taking seriously the question of whether storage or shifted usage is worth more than export. Michigan's own framing of the program says as much, treating the storage-versus-export tradeoff as part of what an installer should model rather than an upsell.
The 110 percent rule
Michigan's 2023 Public Act 235 set the maximum a customer may build at 110 percent of their prior 12 months of usage, alongside the 550 kW project ceiling. On a house, the usage rule is the one that decides the design.
It is a ceiling and not a recommendation. Because exported generation earns less than self-consumed generation saves, the marginal panel on an oversized system is the weakest part of the investment, and an array built to the limit of what the rule permits is not automatically the best one to own.
Bring twelve months of bills to the first conversation. If an installer proposes more capacity than that history supports, ask what the extra is expected to earn and whether that assumes export or self-consumption. The answer tells you quickly how carefully the proposal was built.
Paying for it, without the credit that ended
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. A 2026 purchase in Ann Arbor cannot claim it, and any calculator or quote that still applies it is overstating the return substantially.
The business version of the credit under Section 48E is a different provision and can still matter indirectly. A lease or power purchase agreement provider may claim it and reflect part of the value in the rate they quote you, which is worth asking about directly and checking with a tax advisor before it changes your decision.
For a purchase, Michigan Saves is the state's nonprofit green bank and the financing route most local installers work with. It connects homeowners with participating credit unions for qualifying improvements including solar, battery storage and EV chargers, with rates starting at 5.99 percent APR and terms up to 180 months, conditional on using an authorized contractor and applying through its portal. Check the contractor list before choosing an installer, because eligibility depends on it.