From the Motor City to the Windy City

Now in Chicago

WJ O’Neil Chicago LLC brings 30 years of mechanical service expertise to facilities managers in Chicagoland. Our focus – understand what you need, recommend optimal solutions and deliver fast.

It’s pretty simple. We’ll make your priorities ours – then roll up our sleeves and get them done.

Interested? We'll give you a call. Tell us what you'd like to get done >


  • Controls systems
  • Chillers
  • Boilers
  • Built-up systems
  • Environmental chambers
  • Computer rooms
  • DDC
  • Pneumatic controls
  • HVAC systems of all kinds


  • Preventative maintenance programs
  • Total energy management programs
  • Complete systems design, modernization, or replacement
  • Retrofitting and new installations
  • Full mechanical life warranty service for new installations


  • Multi-unit residential
  • Healthcare / Pharmaceutical
  • Commercial / Office
  • Industrial
  • K-12 and Higher Education

Bringing Jobs to Chicago

WJ O’Neil has a vision for a simpler, more effective way of providing mechanical services. We’re always on the look out for good people who share that vision. If you’ve got a passion for service, please email your resume with cover letter explaining what you could bring to our team.
Click here to apply.