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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

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 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
Response time2 days
20 neighbors recently requested a quote
Recommended by90%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

Replacing an HVAC system does not always include new ductwork. The decision depends on the condition of your existing ducts. If they are in good shape, correctly sized for the new unit, and meet current standards, they can often be reused. However, if the ducts are damaged, poorly designed, or improperly sized, they will likely need to be replaced or upgraded to ensure the new system operates efficiently. An HVAC contractor will assess your ductwork and recommend the best course of action. Typically, ductwork is purchased separately, and a full replacement will add to the overall project cost.

Yes, it is possible. An electrical fire can break out if the compressor has inadequate ventilation. When it overheats but doesn't have a proper thermal cutout, this can cause the motor to short-circuit and catch fire. This risk is exacerbated if flammable materials, like dust and fallen leaves, are clogging the unit. The compressor overheating won't start a fire by itself, but poor maintenance and installation can increase the risk once it hits its breaking point and short-circuits.

If your central AC is not blowing cold air, you should try resetting the system. Many systems have a reset button. Make sure your thermostat is off, then turn off the circuit breaker that powers your AC. Hold the reset button for three to five seconds, then turn the circuit back on. Set your thermostat to cool and choose a temperature cooler than the room. Your system should turn on quickly.

Yes, HVAC zoning is generally considered worth the investment by both experts and homeowners. Zoned systems offer significant benefits in convenience, efficiency, and comfort by allowing you to set different temperatures for various rooms or 'zones' in your house. This ability to heat and cool only the spaces you're using leads to energy savings and lower utility bills. Zoned systems are especially effective in multi-level homes that experience temperature fluctuations, but even smaller homes can benefit from the ability to adjust temperatures more quickly. While the up-front installation cost can be high, many find it's a worthwhile long-term investment, particularly for those who plan to stay in their home for a while.

The best time of year to purchase or replace an HVAC system, including components like an air conditioner or furnace, is during the off-season—spring and fall. During these periods, HVAC professionals are less busy than in summer and winter, when extreme temperatures create urgent demand. Shopping during the off-season can lead to savings of 10% to 15% on an AC unit and allows you more time to find the best deal and other cost-saving incentives. Typically, air conditioning units go on sale in the fall after demand drops, while furnace prices tend to decrease in the spring.

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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