Do solar panels raise your assessment in Illinois?
Illinois provides a special valuation for solar energy systems. It has to be claimed.
Owners considering solar reasonably worry that adding value adds assessment. Illinois addresses this specifically.
The special valuation
Illinois provides an alternative valuation for solar energy systems, allowing the property to be valued as though a conventional system were installed instead — so the improvement does not carry its full added value into the assessment.
It must be claimed
This is the part people miss. It is not automatic. A claim has to be filed with the chief county assessment officer, and until it is, an assessor picking up the improvement from a permit may assess it normally.
What to do
File the claim when the system is installed. Ask your installer whether they handle it — many do not, and it falls to the owner. Then check the following year's notice to confirm it was applied.
If you already installed
Ask the assessor whether the special valuation is in place. If your assessment rose after installation and no claim was filed, that is worth correcting, potentially for prior years.
The home improvement exemption too
Where solar is part of a wider residential improvement, the four-year home improvement exemption may also apply to the added value. They are separate provisions — ask about both.