6 mechanical contractors in Chicago, IL. 4 of them carry a Google rating, from 2.0 to 5.0 stars across 16 reviews — 2 sit at 4.5 or better. 6 list a phone number and 6 a website. Best-rated first; contact them yourself, we don’t resell your details.
Mechanical contractors work on rooftop units, chillers and building-wide systems rather than home furnaces. If you are specifying for a commercial property this is a different set of firms, with different licensing and bonding.