
Serving Herculaneum, MO and surrounding areas
Approved
In business since 2003
Free estimates
Emergency services offered
"A-ok! Dunn OneHour HVAC is always top notch!"



Serving Herculaneum, MO and surrounding areas
Approved
In business since 2003
Free estimates
Emergency services offered
"A-ok! Dunn OneHour HVAC is always top notch!"


Serving Herculaneum, MO and surrounding areas
Approved
In business since 2014
Free estimates
Emergency services offered
"The owner provided me with detailed information about the equipment and installation of my new furnace/ air conditioner. He was through and did a great job of cleaning up after the project was complete. I highly recommend this company and plan to use them in the future."


Serving Herculaneum, 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."





+10

Serving Herculaneum, MO and surrounding areas
Approved
In business since 1954
Free estimates
Emergency services offered
"I’ve used this company twice. My husband has a medical condition that is affected by heat. The first time the air conditioner wasn’t working they made every effort to assess the problem immediately when I explained the medical condition. At the time they corrected the problem I was advised the system was probably 20 years old and we may have to consider a new system soon. The second time I contacted Comfortable Carla’s was about 4-6 weeks later when the system wasn’t working again. This lead to a system replacement. I was provided with different options, my questions were answered and the installation was completed as quickly as possible, especially in view of my husband’s medical issue. The staff was was professional, efficient and kept me apprised all throughout the process. I highly recommend this company."





+1
Serving Herculaneum, MO and surrounding areas
Approved
In business since 1982
Emergency services offered
Warranties offered
Founded in 1982. Team members that are drug tested and background checked insuring that the people in your home are safe. We specialize in repairing and replacing residential heating and air conditioning systems. "Fixed Right or It's Free"\nTechs available Sat & Sun call for appointment.

Serving Herculaneum, MO and surrounding areas
Approved
In business since 1980
Free estimates
Emergency services offered
"Logan was polite, & respectful completed the job in a timely manner. Cleaned up any mess that was made. I will definitely request Logan again for any additional appliance repair I may need."


Serving Herculaneum, MO and surrounding areas
Approved
In business since 2025
Emergency services offered
Credit card accepted
"Had a few issues with my HVAC. Austin was fantastic and fixed everything the same time. Was late"

Serving Herculaneum, MO and surrounding areas
Approved
Free estimates
Emergency services offered
Warranties offered
"Furance was not working, call House Doctor. They were out the next day and got it back up and running. Professional and efficient. Plus, very affordable."





+1

Serving Herculaneum, MO and surrounding areas
Approved
Super Service Award Winner
In business since 1985
Customers say: True professional
"His service was great. He was very professional very friendly knew what he was doing. He went over and above what I expected. I plan on using him again especially this summer. Great guy. Great WORK would recommend him! You can’t go wrong here."





+2
Serving Herculaneum, MO and surrounding areas
Approved
In business since 2008
Credit card accepted
Offers commercial services
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.\n
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.
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