Illinois offers a special assessment of solar energy systems for property tax purposes. When a claim for alternate valuation is filed, the chief county assessment officer is required to ascertain two values: the value of the improvements as if equipped with a conventional heating or cooling system and the value of the improvements as equipped with the solar energy system. The alternate valuation is the lesser of these two values.
Eligible equipment includes both active and passive solar energy systems. The exemption is not valid for equipment that is equally usable in a conventional energy system or for components that serve non-solar energy generating (e.g., structural, aesthetic, insulating, etc.) purposes.
This exemption also does not apply to commercial solar energy systems in counties with fewer than 3,000,000 inhabitants. "Commercial" in this context refers to systems that generate electricity primarily for wholesale or retail sale, not on-site use; the definition does not refer to customer class.
Application for Solar Assessment
Those who wish to have their solar energy property valued in this fashion must file the State of Illinois PTAX-330 property tax form with their local county assessor's office. Forms are available online and through each Illinois county assessor's office.