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4.7

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Verified Reviews for Heating And Air Conditioning Service pros in O Fallon, MO

*The Angi rating for Heating And Air Conditioning Service companies in O Fallon, MO is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Heating And Air Conditioning Service needs.

*The HomeAdvisor rating for Heating And Air Conditioning Service companies in O Fallon, MO is a rating based on verified reviews from our community of homeowners who have used these pros to meet their Heating And Air Conditioning Service needs.

Last update on January 07, 2026

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

8 neighbors recently requested a quote
Recommended by92%of homeowners
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Avatar for Anton's Plumbing, Heating/Cooling & Energy Experts
Anton's Plumbing, Heating/Cooling & Energy Experts
4.7(
513
)

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

Response time1 day
Response rate86%
16 neighbors recently requested a quote
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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

6 neighbors recently requested a quote
Recommended by93%of homeowners
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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

Response time6 days
10 neighbors recently requested a quote
Recommended by93%of homeowners
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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
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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
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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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Heating and Air Conditioning questions, answered by experts

The cost to replace an AC evaporator coil is typically between $600 and $2,500, with an average cost around $1,300 to $1,350. The price of the coil itself can range from $550 to $1,100, depending on the brand, size, and style, with professional labor adding around $700. Replacing a condenser coil is generally less expensive, costing about $800. Because this repair involves handling refrigerants, it requires a licensed AC professional. Regular inspections, which cost between $200 and $600, can help prevent costly coil replacements.

You will only need to refill your AC with refrigerant if it has a leak. Otherwise, a modern, well-maintained AC will most likely never need a recharge. You may notice a leak in an older system if your bills are higher, you hear a hissing sound, or if the air is blowing out hot.

A power outage can damage your air conditioner, just like a power surge can damage any electrical device or appliance. In most cases, your circuit breaker or built-in surge protection on your AC unit protects your AC and just needs a reset. But in other cases, it might be that your AC compressor or capacitor was blown during the power surge. You’ll need to have an HVAC professional repair or replace any AC parts. 

Turn your system off when you're toasty or when you're out to prevent unnecessary wear. Using the timer on your thermostat so that it switches off when it reaches a certain temperature or turns on just before you get back from work is best. An annual maintenance contract can be helpful to ensure your system receives these important services at regular intervals.

No, a furnace is not the same thing as an AC, or air conditioner, but these are both parts of an HVAC system. They both use air ducts to transport cool or hot air around your home to achieve a comfortable temperature set by your thermostat. An AC runs on electricity, while a furnace can use different fuel sources.

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.

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