Top-rated heating and air conditioning pros.

Get matched with top heating and air conditioning pros in O Fallon, MO

There are 19 highly-rated local heating and air conditioning pros.

TRUSTED BY O FALLON, MO HOMEOWNERS

  • Average homeowner rating star icon4.7
    Average homeowner rating
  • Verified reviews icon493
    Verified heating and air conditioning services reviews

Find Heating and air conditioning pros in O Fallon

Avatar for Dunn Plumbing, Heating and Air Conditioning / Dunn One Hour Heating and Air Conditioning

Dunn Plumbing, Heating and Air Conditioning / Dunn One Hour Heating and Air Conditioning

6068 BAUMGARTNER INDUSTRIAL DR
4.71(
256
)
Approved Pro

Dunn Plumbing, Heating and Air Conditioning / Dunn One Hour Heating and Air Conditioning

6068 BAUMGARTNER INDUSTRIAL DR
4.71(
256
)
Approved Pro
Customers say: Super punctual
400 local quotes requested
22 years of experience

Now offering one hour service for heating and air conditioning service. We are factory authorized to service all major brands and we offer all the top products in the industry. Year to year we win numerous awards for customer service and technical skill. Our team is dedicated to providing you with the attention to detail and customer service that can create a whole new level of comfort and energy savings. Led by owner Brett Nejmanowski, our company provides expert sales, service and installation. We have a team of technicians that are fully qualified to help you select the comfort system that best fits your home and your budget. We serve the greater St Louis area, and are a no-nonsense, everything-on-the -table kind of heating and cooling company. Our written 100% satisfaction guarantee is behind all the work we do – if you’re not happy with our heating and cooling services for any reason, we’ll make it right or give your money back, no questions asked! No matter if it is a furnace or AC repair, furnace and AC installation, heat pump installation, or anything heating and air conditioning-related, you will have our guarantee. Along with the services we provide, we’re also passionate about our duty to protect the environment and our social responsibility to the community. In our daily practices, we utilize earth-friendly products and methods to ensure clean outdoor and safe indoor environments for the people we serve. We regularly give back to the community through volunteer work and financial donations. Among the charitable organizations we support are Safe Kids USA, National Multiple Sclerosis Society, Autism Speaks and the Sheriffs’ Association. Financing options available. Numerous rebate programs available. Government subsidized programs available to qualifying homes. Additional phone number (618) 717-0707 Also servicing clients from both 14248 F Manchester Rd, Ste. 190, Manchester MO, 63011 & 110 West Main St., Ste. A, Belleville IL, 62220!

"Very professional and thorough"

Carla F on May 2025

Now offering one hour service for heating and air conditioning service. We are factory authorized to service all major brands and we offer all the top products in the industry. Year to year we win numerous awards for customer service and technical skill. Our team is dedicated to providing you with the attention to detail and customer service that can create a whole new level of comfort and energy savings. Led by owner Brett Nejmanowski, our company provides expert sales, service and installation. We have a team of technicians that are fully qualified to help you select the comfort system that best fits your home and your budget. We serve the greater St Louis area, and are a no-nonsense, everything-on-the -table kind of heating and cooling company. Our written 100% satisfaction guarantee is behind all the work we do – if you’re not happy with our heating and cooling services for any reason, we’ll make it right or give your money back, no questions asked! No matter if it is a furnace or AC repair, furnace and AC installation, heat pump installation, or anything heating and air conditioning-related, you will have our guarantee. Along with the services we provide, we’re also passionate about our duty to protect the environment and our social responsibility to the community. In our daily practices, we utilize earth-friendly products and methods to ensure clean outdoor and safe indoor environments for the people we serve. We regularly give back to the community through volunteer work and financial donations. Among the charitable organizations we support are Safe Kids USA, National Multiple Sclerosis Society, Autism Speaks and the Sheriffs’ Association. Financing options available. Numerous rebate programs available. Government subsidized programs available to qualifying homes. Additional phone number (618) 717-0707 Also servicing clients from both 14248 F Manchester Rd, Ste. 190, Manchester MO, 63011 & 110 West Main St., Ste. A, Belleville IL, 62220!

"Very professional and thorough"

Carla F on May 2025


Avatar for Fresh Air Heating & Cooling

Fresh Air Heating & Cooling

612 Spirit Valley East Dr
4.77(
270
)
Approved Pro

Fresh Air Heating & Cooling

612 Spirit Valley East Dr
4.77(
270
)
Approved Pro
Customers say: Super punctual
Recommended by 91% of Angi customers
Recommended by 91% of HomeAdvisor customers
110 local quotes requested

Fresh Air has been family owned and operated since 1987. Family members Patrick, Tim, Katie and Kevin work together to maintain a culture of excellent service. Fresh Air employs 24 people equally dedicated to constant improvement and a consistent delivery of services. A happy customer is priority #1. Choose Fresh Air and experience the exceptional service you deserve. Fresh Air is a 10-time Super Service Award recipient!! (2009-2021). Additional contact name - Katie Sinn. Additional e-mail - [email protected]

"Great customer service when I called for service. Expert technician that diagnosed the problem and quickly repaired my AC."

Tim R on April 2024

Fresh Air has been family owned and operated since 1987. Family members Patrick, Tim, Katie and Kevin work together to maintain a culture of excellent service. Fresh Air employs 24 people equally dedicated to constant improvement and a consistent delivery of services. A happy customer is priority #1. Choose Fresh Air and experience the exceptional service you deserve. Fresh Air is a 10-time Super Service Award recipient!! (2009-2021). Additional contact name - Katie Sinn. Additional e-mail - [email protected]

"Great customer service when I called for service. Expert technician that diagnosed the problem and quickly repaired my AC."

Tim R on April 2024


Avatar for Anton's Plumbing, Heating/Cooling & Energy Experts

Anton's Plumbing, Heating/Cooling & Energy Experts

950 Bolger Ct
4.67(
484
)
Approved Pro

Anton's Plumbing, Heating/Cooling & Energy Experts

950 Bolger Ct
4.67(
484
)
Approved Pro
Customers say: Super punctual
Recommended by 90% of Angi customers
Recommended by 90% of HomeAdvisor customers
432 local quotes requested

Anton's has been in business for 43 years and maintains an A+ rating with the BBB. We have the highest Google rating in St. Louis. We offer manufacture rebates, and 0% financing for up to 60 months! We currently employ 72 team members who receive customer service training twice per week. Our service technicians have been professionally trained on our 6 step Anton's service system to ensure our customers receive the same GREAT service at a GREAT price each and every visit!! We provide upfront pricing and don't complete any repairs with out approval. We are the only company in St. Louis to offer lifetime warranty on repairs for our UP plan members!!!! Senior Discount- $10 off a service or $100 off complete new system Emergency Service phone number- 314-499-8400

"Did good work, fixed our loose plumbing quickly"

Griffin M on July 2025

Anton's has been in business for 43 years and maintains an A+ rating with the BBB. We have the highest Google rating in St. Louis. We offer manufacture rebates, and 0% financing for up to 60 months! We currently employ 72 team members who receive customer service training twice per week. Our service technicians have been professionally trained on our 6 step Anton's service system to ensure our customers receive the same GREAT service at a GREAT price each and every visit!! We provide upfront pricing and don't complete any repairs with out approval. We are the only company in St. Louis to offer lifetime warranty on repairs for our UP plan members!!!! Senior Discount- $10 off a service or $100 off complete new system Emergency Service phone number- 314-499-8400

"Did good work, fixed our loose plumbing quickly"

Griffin M on July 2025


Avatar for Hosack Plumbing Heating & Cooling

Hosack Plumbing Heating & Cooling

110 W Pitman St
4.78(
333
)
Approved Pro

Hosack Plumbing Heating & Cooling

110 W Pitman St
4.78(
333
)
Approved Pro
Customers say: Super punctual
Recommended by 92% of Angi customers
Recommended by 92% of HomeAdvisor customers
311 local quotes requested

With over twenty-five years of experience in the industry, Hosack Plumbing Heating & Cooling is the right team to trust with all of your plumbing and heating and cooling needs. Our professional St. Louis technicians are highly skilled, extensively trained, extremely knowledgeable, and expertly proficient. We specialize in commercial and residential plumbing as well as residential heating and cooling. Our technicians will do everything possible to ensure that you have the most reliable and efficient plumbing and hvac systems possible.

"Dan and Bill were great to work with and did excellent work. They were fast, professional and friendly"

Clare S on November 2024

With over twenty-five years of experience in the industry, Hosack Plumbing Heating & Cooling is the right team to trust with all of your plumbing and heating and cooling needs. Our professional St. Louis technicians are highly skilled, extensively trained, extremely knowledgeable, and expertly proficient. We specialize in commercial and residential plumbing as well as residential heating and cooling. Our technicians will do everything possible to ensure that you have the most reliable and efficient plumbing and hvac systems possible.

"Dan and Bill were great to work with and did excellent work. They were fast, professional and friendly"

Clare S on November 2024


"He responded very quickly and was able to come out and fix my mini split. I would recommend this company to anyone looking for a fair price and good work. Thanks again! "

Jackie K on October 2025

Good Service Heating and Cooling,LLC. Over 30 years of HVAC experience. Honest and affordable. Do it right the first time.

"He responded very quickly and was able to come out and fix my mini split. I would recommend this company to anyone looking for a fair price and good work. Thanks again! "

Jackie K on October 2025


American Airtemp LLC

1238 Traverton Dr
New on AngiNew on Angi
Approved Pro

American Airtemp LLC

1238 Traverton Dr
New on AngiNew on Angi
Approved Pro
17 years of experience

American Airtemp LLC is committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests and make their concerns the basis of our business.

American Airtemp LLC is committed to excellence in every aspect of our business. We uphold a standard of integrity bound by fairness, honesty, and personal responsibility. Our distinction is the quality of service we bring to our customers. Accurate knowledge of our trade combined with ability is what makes us true professionals. Above all, we are watchful of our customers' interests and make their concerns the basis of our business.


"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!"

Diane K on October 2025

Trusted since 1946, Schraer Air Experts offers top-notch heating, cooling, air quality and hot water services in Warren, Montgomery, St Charles and Lincoln County MO.

"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!"

Diane K on October 2025


Avatar for Oasis Express HVAC

Oasis Express HVAC

11520 St Charles Rock Rd Suite #201
No reviews yet

Oasis Express HVAC

11520 St Charles Rock Rd Suite #201
No reviews yet
6 years of experience

5 Years in Business, we specialize in Heating and Cooling services, Maintenance, Repair and New Installation System, Refrigeration Commercial Cooling and also Mechanical Drawings by a Licensed. Our Team made up of honest, responsible Tech.

5 Years in Business, we specialize in Heating and Cooling services, Maintenance, Repair and New Installation System, Refrigeration Commercial Cooling and also Mechanical Drawings by a Licensed. Our Team made up of honest, responsible Tech.


We specialize in all around home repair, hvac and custom sheet metal fabrication, maintenance, and improvements. The safety and investment of one's home is our top priority.


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Heating and Air Conditioning questions, answered by experts

Excessive humidity in a room often manifests through visible signs like condensation on windows or walls, a musty or damp odor lingering in the air, peeling wallpaper or paint, and the presence of mold or mildew. Experiencing discomfort due to a consistently clammy or sticky feeling can also indicate high humidity levels.

There are several steps you can take to prevent your AC drain from clogging. This includes cleaning the drain line at least every three months, changing the filter every one to three months, and getting your AC serviced annually. Also, if any problems arise with your AC, hire an HVAC technician to deal with them ASAP.

As mentioned above, not all HVAC Schrader valves are necessarily the same. While the valve core and pin or spring size on Schrader valves used for HVAC are generally similar, the valves are not all universal and interchangeable. The size of Schrader valves varies depending on whether it's used in an air conditioner, bicycle tire, or motor vehicle tire.

Most AC repair technicians will take between two and six hours to carry out repairs, depending on the work needed and the accessibility of the unit. For example, recharging refrigerant lines should take one to two hours to service, while replacing a compressor, blower fan, or other major components can take five to eight hours. You can ask your AC repair technician how long they expect the job to take, but just in case, you should plan on being home and available for most of the day.

If your drain line is clogged, your AC might stop cooling, shut down, or refuse to turn on at all. Otherwise, you might see your AC leaking water, find standing water or water damage near the unit, or notice a musty smell coming out of your air conditioner or vents.

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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