What does the One Hour mean in your company name?

The 'One Hour' in our company name indicates our guarantee to be at your home in the predetermined window quoted when you set your appointment. If we do not show up within that window, your service call fee is waived. 1. Express Appointment: This is an appointment that is scheduled during a specified one-hour time slot. You are promised that a technician will arrive at your home within this one-hour time window. You will also receive a call when the technician is en route to your home. 2. Reserved Appointment: This is an appointment that is scheduled during a specified, two-hour time slot. You are promised that a technician will arrive at your home within this two-hour time window. You will also receive a call when the technician is en route to your home. 3. Standard Appointment: This is an appointment that is scheduled during a specified four-hour time slot. You are promised that a technician will arrive at your home within this four-hour time window. You will also receive a call when the technician is en route to your home. 4. Stand-By Appointment: This appointment is for overflow situations. This appointment will not have a specified time. You will receive a call when the technician is en route to your home. 5. Emergency Appointment: This appointment is for an unspecified time after normal business hours Monday – Saturday and all day on Sundays/Holidays. Calls are dispatched in the same order they are received. You will also receive a call when the technician is en route to your home.

Do you service emergencies after-hours?

Yes, we offer emergency services 24-hours a day, year-round.

How much will my service cost?

The size and complexity of your HVAC issue will determine the cost. Because our trained, licensed HVAC technicians must diagnose the issue before we are able to quote you an accurate cost, we require an appointment to be set to complete a diagnostic on your system. Once the diagnostic is complete, your One Hour® technician will walk you through all costs using our Straightforward Pricing® Guide so there are never any surprise fees.

St. Louis, MO

HVAC Service you can count on

4.9

(838 reviews)

Heating & Air Conditioning

Services By One Hour

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HVAC Service Near Me
—Available 24 Hours

One Hour Heating & Air Conditioning understands that heating and air conditioning issues create uncomfortable living situations — especially when temperatures outside are extreme. Luckily, our customer specialists are on standby 24/7 to fix your urgent issues. Whether you need HVAC installation, repair, or maintenance, our HVAC service experts are ready to help.

Emergency HVAC Services

We offer 24-hour emergency HVAC services – even on weekends and holidays – to ensure you have professional support when you need it most. Arriving with service trucks stocked full of specialty parts and tools, we have the equipment needed to fix many HVAC problems on the spot. In the case that additional parts are needed, rest assured – we will do everything in our power to handle your HVAC emergency quickly and efficiently.

Give our team a call today or contact us online to request your same-day HVAC service.

Air Conditioning

Whether you need an emergency replacement, regular maintenance, or installation services, our qualified technicians have the experience and technological resources to get any HVAC job done correctly. We utilize the latest tools, products, and techniques to stay up to date with cutting-edge changes in the industry.

AC Repair

At One Hour Heating & Air Conditioning, our HVAC technicians service all major AC brands and models. Our AC repair team can fix:

Poorly insulated ductwork
Power supply breakdowns
Defective fans or thermostats
Refrigerant leaks
Frozen condenser coils
Blocked condensation drainage
AC short-cycling (turning on and off too quickly)

After inspection, we will provide a detailed estimate.

AC Installation & Replacement

There are many telltale signs that an HVAC unit might need to be replaced. If an HVAC unit is over 10-years old, smells terrible, blows warm air, or produces subpar results as energy bills keep rising, give us a call!

AC Maintenance

For optimal performance, AC units require many parts to work seamlessly together. A single problem can cause a ripple effect of issues. This is why spotting minor malfunctions is critical. With regular maintenance visits, we can ensure your HVAC system is operating smoothly and efficiently. Consider joining our Club Membership for additional customer benefits.

HVAC Services

Common Questions

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Our Happy Customers

Reviews of St. Louis

4.9

(838 reviews)

william cheung

09-17-2025

“A big thank you to Jason for solving our plumbing issues in a professional and timely manner. I used Dunn before for our heating and cooling issues. Now, they will be our "go-to" plumber. Thank you!”

Lake House

09-08-2025

“Very professional and informative”

Paul Whitson

09-02-2025

“One hour/JT Dunn are professionals. Good service (personalized) and timely response. We have them for regular maintenance and emergency service and we are very grateful.”

Mary Glasper

08-26-2025

“Dunn had Robert put here very quickly. Professional and polite, he had the furnace going within 20 minutes!! And a reasonable rate!!”

Avion Ridge

08-18-2025

“always good prompt service. would be disappointing if they couldn't fit me in.”

Carolyn Baker

08-13-2025

“Dunn heating and cooling was easy to work with, polite, fast, and helpful! I would definitely recommend them!”

Mary

08-10-2025

“Our AC went out over the weekend, and a technician arrived at our house very shortly after our call. Robert was very helpful, pleasant and knowledgeable regarding a new system. We believe that we received a very competitive price.”

Donna Macaluso

08-07-2025

“Great guy.Not pushy or anything.Helped us save money”

Connie Holzem

08-01-2025

“Wonderful experience with One hour heating and Cooling and Chad Nathan and crew. They did a wonderful job. Wasnt happy w the trane thermostat so they had Nathan come out early the day after the installation and put a better thermostat in. I was dreading the whole experience but they made it look easy. All very polite and capable. ⭐️ ⭐️⭐️⭐️⭐️”

Barbara Cord

07-31-2025

“Awesome tech! Very professional, very personable, tasks done quickly but thoroughly. Asked if he should remove his shoes. Nice touch!! Great price! Would definitely recommend this company!!!”

Servicing your entire home

Part of the Authority Brands Family

Authority Brands is the leading provider of in-home services, building brands that support the success of franchisees as well as better the lives of the homeowners we serve and the people we employ.