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Find 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
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

"Sam was great. Had a extremely dirty system that would not function correctly or blow cold air. Had High Ridge Heating and Cooling here as he has done work before for me and parents. He took one look and stated we needed to replace entire a/c furnace unit for $3100. Told us it would cost about the same to clean. No way I could afford that so went on Angie's List to find someone and read Sam's review's. He came out and told me the cost at $425 to clean. Which was fantastic. He spent about 2 1/2 to 3 hours and did a wonderful job. Ended up paying total $625 once he was done and asked me before doing anything additional that would cost more. Also since our unit didn't have valves on system to reuse our refrigerant he had to put new in which was part of price increase. Sam, thanks so mich for not trying to take advantage."
A/C replacement
Additional Photos
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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

"Mike was awesome, very knowledgeable and friendly. Efficiently got the furnace running as it should be! Even took the time to educate me on what the issue was and explained what he did to fix it. Highly recommend!"
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+2

Response time6 days
10 neighbors recently requested a quote
Recommended by93%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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17 neighbors recently requested a quote
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

"The repairman came out on time and found the issue immediately. While he was capable of repairing my compressor, he recommended that I contact the manufacturer to take advantage of a warranty repair. His honesty and details for how to quickly engage the warranty service caught me by surprise, and I will not hesitate to call this company anytime I have an issue. I recommend this company."
Additional Photos
Response time2 days
3 neighbors recently requested a quote
Recommended by89%of homeowners
Avatar for Wise Men Heating and Cooling, LLC
Wise Men Heating and Cooling, LLC
5.0(
7
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 2000

Free estimates

Emergency services offered

"The father and son duo was very professional. My emergency happened after typical business hours but they still came out take a look at my thermostat. Very polite and informative. Once the store opened, they got what they needed and returned the next morning. They did an excellent job and are very affordable. I look forward to continuing business with them."
Full furnace
Full furnace
Full furnace
Heating Cooling HVAC
HVAC

+2

Response time7 hrs
Response rate100%
8 neighbors recently requested a quote
Avatar for Schraer Heating and Air Conditioning
Schraer Heating and Air Conditioning
5.0(
8
)

Serving O Fallon, MO and surrounding areas

Approved

In business since 1946

Free estimates

Emergency services offered

"The 3 Mustache Pledge! Schraer Heating and Cooling deserves every bit of praise I can give! I called them about a worrisome noise coming from my system — one that I could only describe through a few rather vague and comical sound effects. Despite my less-than-technical explanation, their technician quickly understood exactly what I meant, found the issue, and had it fixed in no time. Their professionalism, responsiveness, and ability to solve the problem so efficiently (and with good humor!) made the whole experience stress-free. I’m so grateful for their excellent service and expertise. Highly recommend Schraer Heating and Cooling to anyone looking for honest, skilled, and friendly professionals! I will definitely keep my maintenance agreement in full force and effect!"
Airlift rooftop unit
Duct installation
Geothermal job
Crane lift a rooftop unit
Finalize duct on a new construction

+3

Response time1 day
24 neighbors recently requested a quote
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FAQs for air conditioning projects in O Fallon, MO

Most professional HVAC technicians require two to three hours to complete an expansion valve replacement. The timeframe depends on your unit's accessibility and whether additional repairs are needed. The process involves recovering refrigerant, removing the old valve, installing the new component, and recharging the system. Scheduling during less busy seasons may result in more convenient appointment times.

Operating your air conditioner with a malfunctioning expansion valve isn't advisable. Continuing to run the system could potentially damage other components, particularly your compressor, which is significantly more expensive to replace. If you notice performance issues like inconsistent cooling or unusual noises, it's best to have your system inspected before continuing regular use.

Expansion valves don't have a standard replacement schedule, as their longevity depends on system usage, maintenance frequency, and environmental factors. Regular professional maintenance helps identify potential valve issues before they cause system failure. Having your HVAC system serviced annually allows technicians to monitor component condition and recommend preventative replacements when necessary.

Refrigerant leaks require prompt professional attention. If your expansion valve is leaking, you'll likely notice reduced cooling performance and possibly hear hissing sounds near the unit. Addressing leaks quickly prevents further system inefficiency and avoids the environmental impact of released refrigerant. Your HVAC technician will need to repair the leak and recharge the system with the proper refrigerant type and amount.

Because many AC issues present similar symptoms, professional diagnosis is recommended. Problems like inadequate cooling, inconsistent temperatures, or strange noises could indicate expansion valve issues, but might also stem from refrigerant leaks, electrical problems, or airflow restrictions. A qualified HVAC technician has the tools and expertise to accurately identify the root cause and recommend appropriate repairs.

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

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