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TRUSTED BY O FALLON, IL HOMEOWNERS

  • Average homeowner rating star icon4.6
    Average homeowner rating
  • Verified reviews icon347
    Verified heating and air conditioning services reviews

Top-Rated Heating and air conditioning pros in O Fallon - Updated Nov 2026

Avatar for Aire Serv of St. Louis
Aire Serv of St. Louis
5.0(
5
)
Central A/C - InstallGas Furnace / Forced Air Heating System - InstallAir Ducts & Vents - Clean+11 more

Serving O Fallon, IL 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 Allstar Carpet & Upholstery Care
Allstar Carpet & Upholstery Care
4.8(
44
)
Air Ducts & Vents - Clean

Serving O Fallon, IL and surrounding areas

Approved

In business since 2006

Free estimates

Emergency services offered

"Very pleasant experience. I needed a new company and I was so pleased. They did an excellent job. Stains that would always come back after time have disappeared. So fast; so helpful!"
Response time8 hrs
Response rate89%
Recommended by97%of homeowners
Avatar for Healthy Home Pest Control & Services
Healthy Home Pest Control & Services
4.4(
387
)
Air Ducts & Vents - Clean

Serving O Fallon, IL and surrounding areas

Approved

In business since 2017

Free estimates

Emergency services offered

"HIGHLY RECOMMEND! Did much research on companies 1st b/c I was aware of scams with duct cleaning. But this company is very legitimate professional - techs and receptionist, all the way around! Top quality service! On time and will answer any questions and explain it all in great detail? very polite and professional. And yes, they will take photos throughout if you want to see exactly the differences of before and after. I had bought a 1959 home which had never been cleaned. See my before/after photos. Before, I kept having to wipe off my counter tops a few times a day because they always felt gritty. After the duct cleaning, they stay clean now - A HUGE DIFFERENCE! The guys were awesome and went above and beyond by also helping me carry a heavy appliance from upstairs to my basement. Very nice guys! They cleaned up any mess before leaving, like they had never there. You will not regret using their service. Lower Price than others too! Thanks Danny & Cameron! Great Work!"
New Trucks
Duct Cleaning Trailers
New Sign
Response time9 hrs
Response rate95%
498 neighbors recently requested a quote
Avatar for Vital Electric Heating and Cooling, LLC
Vital Electric Heating and Cooling, LLC
4.3(
20
)
Central A/C - Service or RepairDuctless Mini-split A/C - Install or ReplaceGas Furnace / Forced Air Heating System - Install+14 more

Serving O Fallon, IL and surrounding areas

Approved

In business since 2006

Emergency services offered

Small jobs welcome

"They were the only one that were able to come out on a Sunday. Found the problem and got our ac working during a heat advisory. Very satisfied with the results and will continue to use them again. Will recommend them to friends and family."
Full system install
Response time10 hrs
7 neighbors recently requested a quote
Recommended by82%of homeowners
C Hatcher Construction
4.8(
11
)
Thermostat - Install or ReplaceThermostat - Repair or Reprogram

Serving O Fallon, IL and surrounding areas

Approved

Customers say: True professional

"No matter what problem you have, Clint is the man for the job! He not only fixed the plumbing issues I discovered during a remodel but was able to fix the electrical issues, flooring problems, install the cabinets, cut and grout backsplash tile, and fix a handful of minor issues that came up along the way. Clint is on time, dependable, courteous and respectful of your property - he even cleans up afterwards! I could not have completed this project without Clint Hatcher and highly recommend him to anyone who needs work done - you will not be disappointed!!"
Response time1 day
Response rate100%
Recommended by70%of homeowners
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Heating and Air Conditioning FAQs, answered by experts

The size window AC you need depends on the BTU and the size of the room you’re cooling. For a room with 8-foot ceilings, look for about 20 BTU per square foot of the room. For example, a 12-by-12-foot room should have an air conditioner with 2,880 BTU. You can buy something slightly more powerful, but don’t overshoot the BTU for a small room, or you’ll waste energy and have higher bills.

A one-stage air conditioner only has one setting, while a two-stage air conditioner has a high and low setting. A two-stage air conditioner costs between $500 and $2,500 more than a traditional air conditioner, but it has a longer lifespan and helps to increase energy efficiency. To make this decision, you should consider your energy needs and available budget.

Evaporator coils in an HVAC system typically last between 10 and 15 years, which is roughly the same lifespan as the entire AC unit. The longevity of the coils can be affected by usage frequency, environmental conditions, and how well they are maintained. Regular maintenance, such as cleaning and inspections, can extend their durability. If the evaporator coil fails in an older air conditioner, it may be more cost-effective to replace the whole unit rather than just the coil.

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.

Many factors affect how much adding air conditioning will cost you, from the size of your home to the size, type, brand, and installation specifics of the system itself. Chances are, a new central air conditioning system for a 2,000-square-foot house will cost somewhere between $3,900 and $7,900 to install, with an average around $6,000. 

The O Fallon, IL 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.