$50.00 Off Water Heater Installation

Improve the efficiency of your heater

Discount good with coupon only. Not valid with any other offer.

$25.00 Off New Humidifier Installation

Discount good with coupon only. Not valid with any other offer.

$300.00 Off Complete Installation

When installing both new heating and cooling equipment

Discount good with coupon only. Not valid with any other offer.

Furnace Replacement

Why pay for a costly repair on an old furnace? *Restrictions apply, Call for details.

Discount good with coupon only. Not valid with any other offer.

FREE! Service Call

With Any Repair or Replacement

For a limited only time. Call for details. Cannot be combined with other coupons or specials. Must present coupon to get the free service call.

$50.00 Off Air Scrubber Air Cleaner

Discount good with coupon only. Not valid with any other offer.

Carrier Cool Cash

0% APR for 60 Months + Cool Cash Rebates!

Cannot be combined with another offer. Contact us for full details.

Use By

05/31/2026

Free! UV Light or Air Cleaner

With purchase of Infinity® System by Carrier

For a limited time only. Call for details. Cannot be combined with other coupons or promotions.

AC Installation in O'Fallon, MO | Heating Installation Saint Peters, MO | Heating Service Lake Saint Louis, MO

Customer Reviews

What our customers are saying

Have been with them for more than 10 years. They provide exceptional service…from the time they call to remind you about setting an appointment to the actual service day. Derek (and all their other technicians) are knowledgeable, professional, prompt, and open to listening to questions and pay attention to details. Never had a problem with anything. Thank you for a job well done. Good pricing.

Seema Chouhan

Reliable has installed and maintained our last 2 furnaces and AC. Our experience with them has been great. Just yesterday we had an issue with our AC. I talked to Marty and he said he’d have someone out the next day. They even were able to accommodate us with an afternoon call. Derrick arrived promptly on time and had us up and going again in 15 minutes (bad capacitor on the condenser unit fan motor). With the prediction of high 90 temps, we were so thankful to have AC working again.

Keith Scherer

We had a emergency water leak problem with our AC unit in the basement of our recently purchased condo. Called Reliable and Derrick was there within a couple of hours. He was polite, knowledgeable, and friendly. Derrick quickly found the problem and repaired it. He also checked the system overall, pointed our some concerns and answered all my questions. I can’t say enough about how satisfied we were with Derrick and Reliable Heating & Cooling! We would definitely recommend them!!! Thanks again!!!!

Terry Mills

I had a system malfunction on Sunday evening December 12, 2022 on my Carrier Infinity ICS purchased in 2008.I am a first time caller to Reliable. Marty called me back and had his Tech dispatched at 8 AM the next day. The unit had failed and was dangerous to use. He had a new system by the next morning. They installed it and I was completely satisfied with their service and response time. I overwhelmingly recommend Reliable and will be using them from now on.

We have used Reliable Heating and cooling for all of our heating and cooling needs. We needed some water heater work and Ralph came out and took care of it right away. Ralph was very professional and knowledgeable. He got the job done very quickly and everything is working great! I always recommend Reliable to family and friends. They truly are Reliable!

Chris Lopez

Had a small gas leak for a property I was helping a friend sell and we found out late last night. We reached out to Reliable H&C and Derrick was over first thing in the morning. He was friendly, professional and knowledgeable. He answered my questions with a smile. Derrick was a rock star. Will absolutely call him again. Bravo

Connor Kapp

More Reviews Write a review

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