In August Illinois made into law IECC 2009. Furthermore, they have expanded it to ALL structures (read residential) and removed Home Rule from the local governments regarding this issue.
Beside being 16% more stringent, there is a new contractor certification form that requires the contractor to sign off that he installed devices per plan!
http://www.ilga.gov/legislation/publicacts/fulltext.asp?Name=096-0778&print=true&write=
