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Top-Rated Air conditioning pros in Saint Charles - Updated Nov 2026

Avatar for Fresh Air Heating & Cooling
Fresh Air Heating & Cooling
4.8(
277
)
Central A/C - InstallCentral A/C - Install - For BusinessCentral A/C - Service or Repair+12 more

Serving Saint Charles, 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
Additional Photos
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+2

14 neighbors recently requested a quote
Recommended by92%of homeowners
Avatar for Dunn Heating Air Conditioning and Plumbing
Dunn Heating Air Conditioning and Plumbing
4.7(
274
)
Central A/C - InstallCentral A/C - Install - For BusinessCentral A/C - Service or Repair+4 more

Serving Saint Charles, MO and surrounding areas

Approved

In business since 2003

Free estimates

Emergency services offered

"JT Dunn Climate Control won my business by being honest and letting me know what would be in my best interest on the maintenance of two HVAC systems in an industrial building of mine. They were very thorough and saved me a lot of money. Then as part of a renovation project they removed two older systems and replaced them with one, installed four new gas infrared heaters on the dock, repaired an old heater, removed other old equipment, and repaired ductwork. They were excellent in every way. They are reliable and trustworthy. They are definitely going to maintain my systems going forward. And they are now the first HVAC company on my list for any project. Next, I'm going to ask them to quote the replacement of my 18-year-old home HVAC system."
Additional Photos
Response time2 days
17 neighbors recently requested a quote
Recommended by89%of homeowners
Avatar for Liberty Heating & Cooling
Liberty Heating & Cooling
4.8(
46
)
Central A/C - InstallCentral A/C - Install - For BusinessCentral A/C - Service or Repair+3 more

Serving Saint Charles, MO and surrounding areas

Approved

Super Service Award Winner

In business since 2017

Emergency services offered

Warranties offered

"I called, not knowing what was wrong with my air conditioning. They actually gave me a few possibilities, over the phone, one of which turned out to be the Culprit. No charge for the advice, they could have easily rip me off. But didn't. They won't give u the run around, and tell you somethings wrong when it's actually not."
A/C replacement
Additional Photos
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+10

6 neighbors recently requested a quote
Recommended by93%of homeowners
Avatar for Hoffmann Brothers
Hoffmann Brothers
4.5(
43
)
Central A/C - Service or Repair

Serving Saint Charles, MO and surrounding areas

Approved

In business since 2000

Emergency services offered

Credit card accepted

"They were on time, efficient. Quality was excellent with a couple of hiccups, which they resolved the same when it failed inspection on hwh. I fixed furnace air leak myself with metal tape."
Installation
Installation
Heat Pump
Heat Pump
Furnace

+14

13 neighbors recently requested a quote
Recommended by97%of homeowners
Avatar for Hively Home Comfort LLC
Hively Home Comfort LLC
4.8(
49
)
Central A/C - Service or RepairCentral Humidifier - Repair or Service

Serving Saint Charles, MO and surrounding areas

Approved

In business since 2017

Free estimates

Credit card accepted

We take great pride in our experience, expertise, quality, and customer service that we provide to meet the consumer's needs. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. In order to understand the needs and expectations of our customers, we take great care to work and communicate with every customer in a professional manner. Our reputation is based on service, safety, and quality, regardless of how large or small the job.

4 neighbors recently requested a quote
Recommended by64%of homeowners
Avatar for All American Appliance Service Inc
All American Appliance Service Inc
4.5(
531
)
Central A/C - Service or RepairCentral A/C - Service or Repair - For Business

Serving Saint Charles, MO and surrounding areas

Approved

In business since 1980

Free estimates

Emergency services offered

"We called in the morning and given a commitment of between 12pm and 5pm that afternoon. John arrived at 4pm. He quickly diagnosed the problem and added Freon/coolant. He was very professional and we’d definitely hire again when needed. Very satisfied! The Angies List Coupon for $69 covered the trip charge. Total cost was $198."
Additional Photos
Response time2 days
2 neighbors recently requested a quote
Recommended by89%of homeowners
Avatar for Aire Serv of St. Louis
Aire Serv of St. Louis
5.0(
5
)
Central A/C - InstallCentral A/C - Service or RepairCentral Humidifier - Install or Replace+4 more

Serving Saint Charles, 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!

Logo
31 neighbors recently requested a quote
Avatar for On Time Experts
On Time Experts
4.8(
104
)
Central A/C - InstallCentral A/C - Service or Repair

Serving Saint Charles, MO and surrounding areas

Approved

In business since 2006

Free estimates

Credit card accepted

When your home needs help, count on the team that does Whatever It Takes to make it right. On Time Experts Heating, Air & Plumbing, formerly Hosack Plumbing, Heating & Cooling, now brings together the experience of Hosack and Al-Don. We provide trusted heating, cooling, plumbing, and air and water quality services throughout O’Fallon and the Greater St. Louis area.

Recommended by97%of homeowners
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FAQs for air conditioning projects in Saint Charles, 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 Saint Charles, MO homeowners’ guide to air conditioning services

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