There are unlicensed heating and air conditioning contractors performing construction work as well as plumbing work, heating work, etc here in Chicago. By both state and city ordinances, that’s wrong and illegal.
All Chicago HVAC contractors are suppose to be licensed. Besides Chicago and Cook County, many municipalities govern themselves on licensing and permits and you should call the town or city concerning their licensing requirements. It is permissible to purchase licenses town by town as you perform work there. If your Chicago HVAC Contractor does not have a license for the town in which you live, they may be getting them as they go.
All reputable HVAC contractors and the International Building Code , RSES and ACCA and many more organizations should petition to have all Heating Companies to be licensed to purchase a furnace or boiler just like EPA made it mandatory to be licensed to buy, handle and use refrigerants and condensing units. That would help with a lot of the poor repairs we often see in the field with unlicensed HVAC contractors. There are HVAC contractors out there in the Chicagoland area that have no business being out there performing service and installations of heating and air conditioning equipment and the majority of us good contractors know who they are.
Homeowners, it is permissible and your right to get a copy of the contractors insurance and license with you as the certificate holder on the insurance certificate.
In closing, licensing is important but not the end of the world. Choose your contractor wisely, check them out and trust your gut feelings about the contractor you like, because your feelings are usually right!