The Hill Group proudly celebrated its 75th anniversary in 2011. The original corporation was founded in 1936 as L.C. Kohlman, Inc. and only performed refrigeration maintenance. The late James B. Hill, P.E., was hired less than a year later as the firm’s engineer. Soon thereafter, the fledgling company was selected to be the local distributor of DuPont’s new Freon refrigerant – with the right to distribute it nationally.

The company survived World War II as a large servicing agency while also installing major piping systems in defense plants. Federal Ventilation Co. was formed in 1946 to provide the firm with sheet metal capability for the young air conditioning market. In 1961, James B. Hill became president of both firms, which he ultimately purchased.

Over the next half century, three generations of the Hill family and many loyal, talented associates steered our organization through additional milestones, growing it into the largest trade contractor in Illinois, with over 1,000 people and more than $290 million in annual revenue.

1970 – 1979

  • Moved to 4241 N. Ravenswood in Chicago, tripling the firm’s available space
  • Plumbing department established
  • Founder L.C. Kohlman dies

1980 – 1989

  • Warren Hill, P.E. becomes president
  • Service department becomes separate corporation
  • First CAD drafting computer purchased
  • Sheet metal shop acquires plasma table and initial automatic duct line stations
  • Federal Ventilating Co. becomes Hill/Wendt Corp.
  • Bob Krier hired as Project Engineer
  • All firms put under Hill Mechanical Group banner

1990 – 1999

  • Purchase of 45,000 square foot building at 1801 W. Berteau
  • Hill Mechanical Operations founded
  • James B. Hill II joins the firm as Project Engineer
  • L.C. Kohlman, Inc. and Hill Wendt Corp. become Hill Mechanical Corp.
  • Seven-year Project Engineer training program formalized

2000 – 2010

  • James B. Hill dies
  • Bob Krier becomes President of Hill Mechanical Corp.
  • 3-D CAD licenses purchased and BIM (Building Information Modeling) initiated
  • Joined Mechanical Contractor’s Information Exchange Group (MCIEG)
  • Comprehensive Solutions established, with expertise in energy efficiency and sustainability
  • Moved to 138,000 square foot facility in Franklin Park, Illinois
  • Hill Mechanical Corp. hires Robert W. Hill as Project Engineer
  • Testing & Balancing and Commissioning groups formed
  • Total group revenues exceed $289 million with over 1,000 employees
  • Integrated Product Delivery (IPD) and Building Information Modeling (BIM) become major focus
  • Group expands with the formation of Hill/Ahern Fire Protection
  • Hill Facilities Solutions established to offer bundled facilities management services
  • Organization’s name is officially changed from Hill Mechanical Group to The Hill Group to more fully encompass its scope of services
  • The Hill Group expands its Franklin Park campus with the acquisition of three additional buildings now on a total of 27 acres
  • Named Top Chicago Workplaces by Chicago Tribune


  • The Hill Group celebrates 75 years of growth and success, spanning three generations of the Hill family
  • ENR magazine names Hill the Midwest’s Top Specialty Contractor of the Year
  • MCA Chicago recognizes Hill for having the best safety record for the year in the 250,000-500,000 hour category


  • Hill Architectural Systems established to offer design, installation and fabrication of metal enclosures for buildings
  • Joined American Contractors Insurance Group (ACIG)
  • Hill presents at the Autodesk BIM Summit in Korea


  • Hill delivers the most Trade Ally electricity savings for ComEd in the fifth year of the program
  • Company awarded the prefabrication of more than 120 bathroom modules for healthcare client
  • New coil line (duct-forming) machine is installed in company’s Sheet Metal Shop
  • Hill President Bob Krier dies unexpectedly


  • James (Jim) B. Hill II named President
  • Superior Mechanical Systems joins the Hill Fire Protection Team


  • Able acquires HMO


  • Precision Control Systems (Indiana) joins forces with Hill