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4.7

(1.2k reviews)

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

Not if you have a standard unit. Because portable AC units actually work to dehumidify the room, you’ll likely need to drain the unit from time to time—but you won’t have to put water into it. There is, however, another type of air conditioner called a swamp cooler that requires water to operate. If you have a swamp cooler, you may need to fill a reservoir with water and potentially ice. But a swamp cooler is different from a standard portable AC unit.

Winterizing can still help you save money on energy costs and help prepare your AC for its work next year when you turn it back on. We suggest planning for at least some maintenance, even if winters are mild in your area.

To diagnose a bad HVAC or AC damper, assess the airflow from your vents. For a manual damper, close it, run your system, and check for airflow. If air is still coming through the vents, the damper is likely faulty and needs repair or replacement. For an automatic damper, turn on your HVAC system and monitor the airflow and room temperature. Signs of a problem include low airflow, a room that won't maintain its set temperature, or a drafty feeling. If you suspect a faulty automatic damper, you may need to hire a professional for repairs.

It all depends on the unit’s SEER (seasonal energy efficiency ratio). A higher SEER rating means better efficiency and lower costs for your energy bills. 

Take a look at the product you’re considering purchasing and compare it to other models to decide which one is affordable upfront but will keep your energy costs low over time.

If there’s a freon leak in your home’s AC unit, it will cause the system to work overtime to cool the house. That issue will result in higher energy bills and it will take much longer for cool air to disperse throughout the home. If your system has a freon leak during the summer, it can make hot days miserable. That’s why it’s important to hire an HVAC professional to resolve a freon leak as quickly as possible.

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.