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

A non-maintained AC is more likely to perform poorly, increase your energy bills, and undergo more severe issues like breakage and water damage. That’s why DIY cleaning or professional maintenance is recommended annually. Otherwise, you might end up paying more in the end than you would for annual service. You can purchase cheap AC cleaning kits if you prefer going the DIY route.

Here’s how AC professionals will clean your AC coils:

  1. Unplug the AC unit or turn off the breaker to the unit in your circuit breaker box.

  2. Remove the faceplate.

  3. Spray a vacuum hose attachment or compressed air can to remove debris, dust, dirt, and grime.

  4. Use a soft-bristled fin comb to remove stubborn caked-on debris.

  5. Use the vacuum hose to suck up any extra debris.

  6. Take a coil-safe cleaning solution and spray it onto the coils. Try to choose a no-rinse solution.

  7. Let the solution sit for at least 15 minutes.

  8. Gently wipe away loosened grime and debris with a microfiber cloth.

  9. Reattach the faceplate, plug in your AC system, or turn the breaker back on.

The cost of annual maintenance depends on the type of HVAC system you have. AC service typically costs an average of $200 but ranges from $100 to $550. If your system needs repairs, the price will vary significantly depending on what needs fixing. However, addressing the issues as they arise can prevent further damage to your unit and keep it operating efficiently for much longer.

On a summer day, expect your AC to run between 12 and 16 hours. However, this time frame depends on just how hot it is outside and the comfortable temperature you’re hoping to maintain indoors. Assuming the size of your AC is appropriate for the space you’re trying to cool, it shouldn’t be a problem for it to work this many hours.

You should get anywhere from three to five quotes for HVAC replacement to get an idea of the average cost of a new unit. Although this quote-collecting process can be time consuming, it allows you to compare what work is required, what type of unit you should install, and how much you should expect to pay for the service.

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.

See all articles