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TRUSTED BY O FALLON, MO HOMEOWNERS

  • Average homeowner rating star icon4.7
    Average homeowner rating
  • Verified reviews icon1.2k+
    Verified heating and air conditioning services reviews

Find Heating and air conditioning pros in O Fallon

Avatar for Fresh Air Heating & Cooling
Fresh Air Heating & Cooling
4.8(
277
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 1947

Free estimates

Emergency services offered

"Great Experience. I was concerned about the 22 yr age of our air conditioner able to keep working and wonder if a long wait time to get a product shipped like refrigerators last year, I called for a quote and within a week it was installed and working! Installers worked tirelessly until their work was done, clean and neat!"
Fresh Air Van
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+2

11 neighbors recently requested a quote
Recommended by92%of homeowners
Avatar for Dunn Heating Air Conditioning and Plumbing
Dunn Heating Air Conditioning and Plumbing
4.7(
273
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 2003

Free estimates

Emergency services offered

"Our tech Robert installed an intake pipe for our HVAC unit to the outside. Tech arrived and completed the work to specifications. We will continue to use Dunn for our HVAC needs going forward. Thank you!"
Additional Photos
31 neighbors recently requested a quote
Recommended by90%of homeowners
Avatar for Anton's Plumbing, Heating/Cooling & Energy Experts
Anton's Plumbing, Heating/Cooling & Energy Experts
4.7(
514
)

Serving O Fallon, MO and surrounding areas

Approved (Corporate)

Super Service Award Winner

In business since 1979

Free estimates

Emergency services offered

"I always recommend Anton's to family and friends who need HVAC services. Their prices are reasonable, and their service is top notch! All of their technicians are very professional and considerate and they don't try to sell you things you don't need. Ronan just came out this morning to do our annual A/C inspection. The service was excellent as always. He took the time to explain everything and made recommendations. I never felt pressured, and I trust this company to take care of my HVAC needs. They've got a customer for life!"
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+18

19 neighbors recently requested a quote
Recommended by92%of homeowners
Avatar for Liberty Heating & Cooling
Liberty Heating & Cooling
4.8(
46
)

Serving O Fallon, MO and surrounding areas

Approved

Super Service Award Winner

In business since 2017

Emergency services offered

Warranties offered

"Liberty did a fantastic job identifying and rectifying airflow problems with our existing Hvac system that was installed less than two years ago by another company. They were punctual, responsive and incredibly knowledgeable. I highly recommend them."
A/C replacement
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+10

5 neighbors recently requested a quote
Recommended by93%of homeowners
Avatar for Hosack Plumbing Heating & Cooling
Hosack Plumbing Heating & Cooling
4.8(
344
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 2009

Warranties offered

Credit card accepted

"Awesom. Highly recommend Glen. We bought new refrigerator and needed new updated waterline installed. Since we had plumber in house wanted to update things we knew we needed done eventually."
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+2

8 neighbors recently requested a quote
Recommended by93%of homeowners
Avatar for All American Appliance Service Inc
All American Appliance Service Inc
4.5(
528
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 1980

Free estimates

Emergency services offered

"Great! Professional, on time , left area clean. Gave us an estimate on our washing machine repair and plan to follow up with this service. I would highly recommend this company. I was called by this company and they sent out a repairman from All Type Appliance Repair. I would highly recommend them!"
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3 neighbors recently requested a quote
Recommended by89%of homeowners
Avatar for AAA Home Services
AAA Home Services
4.9(
9
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 1970

Warranties offered

Small jobs welcome

"I highly recommend AAA home services. They installed a brand new HVAC system and the entire process was trouble free every step of the way. I have had them out to service the system twice a year and the scheduling to do so is easy and the service has been excellent. AAA home services has always communicated well and I have had them do exceptional plumbing work including the installation of a hot water heater. Thank you AAA home services."
AC units from American Standard
HVAC Installation
HVAC Installation
Avatar for Anton's Plumbing, Heating/Cooling Energy Experts
Anton's Plumbing, Heating/Cooling Energy Experts
4.6(
81
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 2000

Free estimates

Emergency services offered

"Both the estimator Kevin the two installers who visited my home were very professional and kind. They answered all my questions and provided a very reasonable price for the installation of the attic insulation. I feel I was very informed on the federal rebate that was available for this installation, as well as on the recommendations of quantity of insulation I needed per residential standards and codes. I would recommend Anton and will use them in the future for my HVAC needs!"
Response time6 hrs
Recommended by95%of homeowners
Avatar for Aire Serv of St. Louis
Aire Serv of St. Louis
5.0(
5
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 2024

Free estimates

Emergency services offered

Looking for reliable HVAC service in St. Louis? Aire Serv of St. Louis is your local expert for residential and commercial heating and cooling. From emergency AC repair during humid Missouri summers to furnace maintenance before the winter chill, our professional technicians are available to keep your home comfortable. We pride ourselves on transparent, upfront pricing, no overtime charges, and the "Done Right Promise." Whether you need a system replacement, duct cleaning, or a routine tune-up in Fenton, Webster Groves, or Kirkwood, we are the team you can trust. Breathe easy with Aire Serv—your comfort is our top priority. Call us today to schedule your service!

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21 neighbors recently requested a quote
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Heating and Air Conditioning questions, answered by experts

While most air conditioners can last between 10 and 20 years, they will only last this long (or longer) if properly taken care of. Routine maintenance and inspections help keep your AC unit running in tip-top shape but understanding what factors will decrease its lifespan will also help keep your unit running cool.

Some things that shorten your AC’s lifespan include:

  • Extreme outdoor conditions, like high humidity or extensive salt spray 

  • Improper installation

  • Extended run times, either by the unit being too small or the thermostat setting too low

  • Not performing required maintenance

To reset your air conditioner, start by turning it off at the thermostat. Then, shut off power to the AC system at the circuit breaker. Some units have a dedicated "reset" button; if yours does, press and hold it for three to five seconds. If your air conditioner doesn't have a reset button, or if you are resetting it after a power outage, leave the circuit breaker off for at least 30 minutes to allow the system to reset itself. Afterward, turn the power back on at the breaker, turn on the AC from the thermostat, and set it to "cool" to test the system.

The size window AC you need depends on the BTU and the size of the room you’re cooling. For a room with 8-foot ceilings, look for about 20 BTU per square foot of the room. For example, a 12-by-12-foot room should have an air conditioner with 2,880 BTU. You can buy something slightly more powerful, but don’t overshoot the BTU for a small room, or you’ll waste energy and have higher bills.

A blocked return air vent can cause your HVAC system to work much harder and, therefore, less efficiently. The result is higher utility bills and poorer air quality. A blocked return air vent can also cause unpleasant dust, dander, and odors to linger in your home’s air.

NATE (North American Technician Excellence) certification is not legally required for HVAC technicians in most areas, but hiring a professional with this certification is highly recommended. NATE-certified technicians demonstrated their expertise and proficiency in different types of HVAC systems, offering assurance of quality service. It's a voluntary certification, yet it indicates a commitment to professionalism and ongoing training. Choosing a NATE-certified technician often means you're working with someone who is up-to-date on industry standards and best practices, which can lead to better service, energy efficiency, and long-term cost savings.

The O Fallon, MO homeowners’ guide to heating and air conditioning services

From average costs to expert advice, get all the answers you need to get your job done.