SIA Blog

What the numbers actually say about home solar

Original research and plain-English explainers on residential solar economics. We publish the method and the data alongside the conclusion — including the parts that do not help us sell anything.

Latest research Measured annual sunlight on an Illinois roof, with the modelled solar panel layout outlined.

Research 7 September 202612 min read

Is solar worth it in Illinois? We modelled 46 real homes to find out

We ran the SIA calculator over a random sample of detached houses across Ameren Illinois territory — every roof measured individually, nothing hand-picked. The federal tax credit is gone; Illinois Shines is not. Here is what that leaves a homeowner.

8.4 yrsMedian payback
10.8%Median return
44/46Worth doing

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