Not Too Hot. Not Too Cold. Just Right

HVAC technician with heating and cool temperature gauge | Heating and Cooling Services for the Missouri and Illinois Bi-State Area by Weir Heating and Cooling in Cahokia, IL

Residential, Commercial, & Custom HVAC Services

When you need your HVAC system repaired or replaced, you want Weir Heating & Cooling in your corner. Located in Cahokia, IL, we serve homes and businesses through the Illinois and Missouri Bi-State area with first-rate HVAC services.

As a local, family-owned HVAC contractor, we believe in providing high-quality heating and cooling products to our customers, who we also consider our neighbors. Whether you need a simple repair, a brand new HVAC system, or custom ductwork, Weir Heating & Cooling has the knowledge and expertise to get the job done quickly, efficiently, and at a competitive price.

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Weir Heating and Cooling staff standing in front of maintenance truck | HVAC Company in Cahokia, IL

Our Story

Our story of giving customers superior heating and cooling service began in 1983 when Tim and Barbara Weir started repairing family members’ and friends’ HVAC systems out of their garage. News of the Weir’s efficiency soon spread, and they opened a small shop in town that attracted many local customers. Years later, Weir Heating & Cooling moved to a larger office where they currently tackle problems with heating and cooling in the Missouri and Illinois Bi-State area.

Our Team

Even in the face of difficulty, Weir Heating & Cooling has proven to be a firm establishment that customers can trust. Despite facing hardship and loss, Barb has managed to maintain and grow the business with the help of Tom, brother of the company’s staple, Tim, who passed away in August 1994. The high level of customer service that the company was founded on continues to be the basis by which Tom, Barb, and their HVAC technician team do business.

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Why Choose Us?


Weir Heating & Cooling has nearly 40 years of experience serving customers with exceptional HVAC services. No job is too simple or too complicated for us. We have the knowledge, expertise, and resources to ensure your satisfaction.


Our material is of the highest quality. We never shortchange the customer by using products that will break down shortly after installation. We even offer a warranty that dispatches a technician to your home or business in the event that an installation or repair goes wrong.

Customer Service

All of our staff members place the customers’ desires at the forefront and go the extra mile when it comes to service. We strive to be timely and leave our customers well-informed about their new or repaired system. We value your trust and would never betray it by being unresponsive in times of need.

“These guy is the real deal!! Had a 25yr old system that I’d been nursing for last 7-8 yrs. Decided to upgrade using Ameren incentives..
New furnace and air conditioner…saving full 25% … Mr. Weir and his team were
Very professional and organized!!!Highly recommend!!”

-Thomas H.

“I highly recommend Weir Heating & Cooling. My grandfather was a contractor for many years and used them on his home builds. I have personally used them now for a few years with a couple HVAC projects. I did a dual zone for my basement and most recently with a new furnace replacement. They have been very efficient, easy to work with and have very reasonable prices.”

-Jason D.

I could not be more pleased with the amazing work completed by Weir Heating and Cooling. Not only were they the best bid but the work they did and the short amount of time they completed it in was spectacular! I had an outdoor unit and coil replaced and they ran additional duct work and opened up a return and they did the job in one morning!!! Thanks again for a job well done!”

-Kelly T.

Knowledgeable staff, you can trust they will make the right repair and give you options for the future to upgrade to an energy efficient unit when the time is right. They won’t pressure you. I like to support small family businesses.”

-Melinda K.

Fast response when my heat wasn’t working great prices I will always have them do work for my family and friends. If you want a professional service call them.”

-Joshua M.

We use Weir Heating and Cooling because of their great quality service. They are priced well, honest, and always right on time. I absolutely recommend them to anyone in the Cahokia area.”

-Kerry A. 

Have a question about our services? Call us at 618-632-6382 or 314-351-2424 today!



Monday-Friday: 8:00 AM-4:00 PM