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One Hour Heating & Air Conditioning® Serving O'Fallon

4.83

(176973 reviews)

Heating & Air Conditioning Services in O'Fallon, MO

When you search for HVAC services in O’Fallon, MO, you want a team that combines technical expertise, dependable response times, and a dedication to customer satisfaction. That’s exactly what you’ll find with One Hour Heating & Air Conditioning® of St. Louis, proudly extending our exceptional heating and cooling services to residents and businesses in O’Fallon.

We’re not a distant operation; we consider O’Fallon part of our home turf. Every service call here gets our full attention, on our clock, with our reputation on the line. From routine maintenance to emergency repairs and full system replacements, we deliver local HVAC solutions backed by national standards of excellence.

Call One Hour Heating & Air Conditioning today for reliable and professional HVAC services in O’Fallon, MO—your comfort is just one call away!

Why Choose One Hour Heating & Air Conditioning® of St. Louis for HVAC Services in O'Fallon, MO?

Faster Response, Punctual Service - As part of the One Hour family, we adhere to the promise: arrive within your scheduled window or your service call is on us. That means you can trust us with your time — we don’t show up “sometime today.” We aim to be prompt, efficient, and respectful of your schedule.
Certified, Skilled Technicians - Our team in O’Fallon is staffed with licensed, trained, and background-checked HVAC professionals. You can count on transparent diagnostics, clear explanations, and honest recommendations. We’ll never try to oversell you or perform unnecessary work.
StraightForward® Pricing - Before starting any job, we walk you through our pricing options. No hidden fees. No surprises. You’ll know exactly what you’re paying and why — whether for repair, replacement, or maintenance.
100% Satisfaction Guarantee - We back our services with a two-year guarantee on labor and materials. If parts fail or workmanship isn’t up to standards, we’ll make it right — because your comfort and confidence matter most.
24/7 Emergency HVAC Support - Heating or cooling fail at the worst time? We’ve got your back. Our technicians are available around the clock, all year long, for urgent HVAC calls in O’Fallon and nearby areas.

Our HVAC Offerings in O’Fallon, MO

We provide a full spectrum of services so you can rely on a single team for all your heating, ventilation, and air conditioning needs:

HVAC Repair & Troubleshooting
Whether your furnace won’t ignite, your air conditioner struggles to cool, or your ductwork has leaks, we diagnose and repair all major brands and systems.
Heating System Services
From furnace maintenance and repair to installing modern heat pumps, we ensure your home stays cozy and reliable even in O’Fallon’s coldest months.
Air Conditioning Services
We repair, maintain, and install AC units. We also offer seasonal tune-ups to keep your system running efficiently, prolonging its life and reducing energy costs.
System Replacement & Installation
If your current system is outdated or underperforming, we’ll help you select and install a new, energy-efficient HVAC system tailored to your home’s needs.
Preventive Maintenance Plans
Regular checkups catch minor issues before they become major headaches. Our maintenance plans help keep your HVAC system efficient and dependable.
Indoor Air Quality Enhancements
From air purifiers and UV lights to humidifiers, dehumidifiers, and upgraded filtration, we improve your indoor comfort and air quality.
Smart Thermostats & Control Solutions
We offer smart, programmable thermostats that help optimize energy use, adapt to your schedule, and give you control no matter where you are.

Schedule your appointment with One Hour Heating & Air Conditioning today and experience fast, dependable HVAC services in O’Fallon, MO you can trust!

What to Expect When You Call Us

When you reach out for HVAC services in O’Fallon, MO, we make the process smooth, transparent, and worry-free from start to finish. Here’s what you can expect:

Prompt Scheduling & On-Time Arrival – We respect your time. Our technicians arrive within the scheduled appointment window, or your service call is free — that’s our On-Time Guarantee.
Friendly, Professional Technicians – Every member of our team is licensed, background-checked, and trained to deliver courteous, expert service with clear communication at every step.
Comprehensive System Inspection – We thoroughly assess your HVAC system to pinpoint issues and recommend the best, most cost-effective solutions for your home or business.
StraightForward® Pricing – You’ll always receive transparent pricing before any work begins — no hidden fees, no surprises, just honest service.
Clean, Respectful Workmanship – Our technicians wear shoe covers, use protective mats, and leave your space spotless once the job is done.
Efficient, Lasting Repairs or Installations – Whether it’s a simple tune-up or a full system replacement, we use high-quality parts and proven methods for reliable performance.

Learn more about our St. Louis-based HVAC experts.

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We Have a Reputation

For Being Punctual, Friendly and Knowledgeable

4.83

(176973 reviews)

Rich Thornton

in the last week

“Derek came out to troubleshoot an issue with water dripping from the return. He identified the problem and fixed it within minutes. He was also the technician that came out when we needed a new A/C unit installed. He is a true professional and is very knowledgeable. I highly recommend One Hour Heating and Air Conditioning.”

James Stephenson

in the last week

“Jordann with One Hour was very professional in her greeting and explanation of the service being performed. She gave a good detailed closing review and sold me on her teams Benny cleaning service I’ll do in the spring. An excellent service technician. Please assign her to my account when service is needed.”

Chris Mccormack

in the last week

“Kamal, what can I say about this guy, first of all very professional, fast he took the time to explain everything he was doing and why. Answered all my questions to my satisfaction. Went over everything more than once lol.. to make sure I understood. He found the problem fast fixed it and I very happy one hour employs such wonderful employees. Very happy with Kamals work and his presence at my home. Thank you. Aloha..”

Lee Francis

in the last week

“They cleaned our dental clinic over the weekend. Great service, very professional, affordable too. Equipment areas were spotless. Staff felt comfortable working Monday morning.”

JAA Shwaa

in the last week

“I had a new furnace and ac installed. Jonny and Tyler B did an amazing job from start to finish. They are both very good at what they do. They had to install new lineset for my new system and it came out looking awesome (even the city inspector commented on how good it looks). The sheet metal work on the new furnace that Jonny fabricated looks amazing as well. I will recommend One Hour Heating and Air to anyone and I can't thank Jonny and Tyler B for the awesome job they did!!”

Jimmy John

in the last week

“Matthew did a fantastic job. Arrived on tome, explained issues he found during his inspection. Very satisfied with his work.”

robert lock

in the last week

“This is a great company with great technicians! Christian was personable, punctual, professional, knowledgeable, and efficient! He fixed my problem and answered all of my questions. I was so impressed that I asked about their maintenance contracts and ended up buying one at a very reasonable price! I highly recommend this company to all homeowners! I couldn't be more satisfied!”

Roblin Cronin

in the last week

“The entire staff is very professional. They get here on time and get the job completed. I highly recommend them and are affordable than other companies. Mr. Calvin is wonderful! LeAnn works a awesome job at multi tasking . Company is AWESOME!!”

Tonia Griffiths

in the last week

“Jeremy Brown was excellent and friendly. Explained the system and services he provided and suggested. Went over cost and repairs and gave feedback on what to keep in mind! Definitely would suggest this company and technician for any future needs.”

kyle mai

in the last week

“Jim and Ashton did an outstanding job installing our new AC and furnace! From the moment they arrived, their professionalism and expertise were evident. They took the time to explain the entire installation process, answered all our questions, and made sure we understood how everything worked before they left. The installation itself was seamless and efficient. Jim and Ashton paid close attention to detail, ensuring everything was set up perfectly and that our home was left spotless afterward. They were courteous, respectful, and truly went above and beyond to make sure we were comfortable with the new system. We couldn’t be happier with the quality of their work and the level of service provided. If you’re looking for trustworthy, skilled professionals for your HVAC needs, look no further than Jim and Ashton. Highly recommended!”

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