Furnace Replacement in Cary, IL | Furnace Service Dundee, IL | Heater Installation Carpentersville, IL

Emergency HVAC Service 24/7 Support

We understand that HVAC issues can arise unexpectedly, which is why we offer emergency service to our customers in McHenry County, Lake County & Northwest Cook County, IL. Our technicians are available 24/7 to address urgent heating and cooling problems, ensuring your comfort and safety.

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Proudly Serving McHenry County, Lake County & Northwest Cook County, IL

Algonquin, IL
Barrington, IL
Carpentersville, IL
Cary, IL
Crystal Lake, IL
Fox River Grove, IL
Huntley, IL
Island Lake, IL
Lake in the Woods, IL
Lake Zurich, IL
McHenry, IL
Wauconda, IL
West Dundee, IL
and more!

Service Areas

Award Winning Service

Our dedication to excellence has earned us a reputation as an award-winning service provider in McHenry County, Lake County & Northwest Cook County, IL. We attribute our success to our focus on customer satisfaction, our highly skilled technicians, and our use of state-of-the-art equipment and techniques.

Hear From Our Community

     EXCELLENT  
     Based on 43 reviews 
    
 
 
   
 
 
        
   Joseph Anzalone 
 2022-11-24
 
 
 Trustindex verifies that the original source of the review is Google. Always a great experience!!!!!!
  
 
       
   David 
 2022-11-18
 
 
 Trustindex verifies that the original source of the review is Google. O'Leary does excellent work, they're honest, and they don't stop until a job is done right.  Highly recommend!
  
 
       
   Don Cashmore 
 2022-11-15
 
 
 Trustindex verifies that the original source of the review is Google. Danniell came over and did a great job and replacing my thermostat. I would highly recommend the service is there a timely efficient and well worth the charge. You will enjoy how they do business!
  
 
       
   Katherine Tracy 
 2022-11-15
 
 
 Trustindex verifies that the original source of the review is Google. I have used O’Leary for over 10
Years at every property I have owned. In the past 10 years I have purchased  2 furnaces and 1 AC unit that they installed and have maintained.

They also have installed radient heated floors that are one of my favorite features of our home.
  
 
       
   Ginger Falcone 
 2022-11-13
 
 
 Trustindex verifies that the original source of the review is Google. Recently moved
  
 
       
   Laurence Ensslin 
 2022-11-10
 
 
 Trustindex verifies that the original source of the review is Google. when it comes to sheet metal, furnace / a/c installation these guys know there business. I have used them for years both commercial and residential. Vince O'Leary is the man to know when it comes to HVAC.
  
 
       
   Rick Lavacchi 
 2022-11-10
 
 
 Trustindex verifies that the original source of the review is Google. Quality installation at a fair price. Vince is very knowlegable and he stands behind their work. Great techs. Highly recommend.