Denison is one of Grayson County’s most established cities, with a historic downtown that just won the Greatest American Main Street Award in 2025 and neighborhoods that have been around for decades. The homes here are not new construction. They’re established properties with HVAC systems that have real history behind them, and they need a company that knows how to work on all of it. Adon Complete Air Conditioning and Heating has been providing heating and air conditioning service in Denison, TX, for years, and we run calls here regularly. We’re based in Anna, just down Highway 75, and we’re available 24 hours a day, 7 days a week.
The Reality of HVAC in Denison
Denison homes tend to be older, and the HVAC systems reflect that. Our technicians have found evaporator coils in Denison that have never been cleaned, condensers blocked so severely with debris that they could only cool the air by 6 degrees, blower motors that have failed from years of restricted airflow, and R-22 refrigerant systems that are beyond repair and need replacement. We have also found plenty of systems in great shape that just need regular maintenance to stay that way.
The point is this: if you have not had your system serviced in a while, Denison is a place where that matters. A system running at 6 degrees of cooling when it should be running at 18 to 20 is working twice as hard for half the result. Getting a set of professional eyes on it costs a fraction of what an emergency repair costs in August.
HVAC Services We Provide in Denison
AC Repair. We carry common parts on our trucks and handle all makes and models. We resolve most Denison repair calls in a single visit.
AC and Heating Installation. When a system is beyond repair or simply not worth fixing, we provide an honest assessment and a clear replacement price. Every new installation comes with up to a 10-year labor warranty.
HVAC Maintenance. Our Adon Care Club is $12 a month and covers two seasonal tune-ups, priority scheduling, repair discounts, no diagnostic fees, and 24/7 emergency access. A maintenance visit helps us catch failing capacitors, clogged drain lines, and dirty coils before they become emergency calls.
Air Duct Cleaning. Older Denison homes often have ductwork that has accumulated years of debris. Our technicians have recommended full system cleanings on multiple Denison service calls this year. A thorough duct cleaning makes a real difference in both air quality and system efficiency.
Air Duct Repair and Sealing. Rodent damage, disconnected ductwork, and aging flex duct are common in Denison homes. Leaky ducts can account for 20 to 30 percent of your system’s output loss. We find and fix them.
Indoor Air Quality. Years of accumulated dust and biological growth on evaporator coils and in ductwork are a real issue in established homes. We offer air filtration systems, UV purifiers, and a free “What Are You Breathing?” screening for Denison homeowners.
Mini-Split Installation. For Denison homes with additions, sunrooms, or spaces where extending ductwork is not practical, mini-splits provide clean, independent cooling and heating without touching the central system.
Heat Pump Installation and Repair. We install and service heat pump systems throughout Denison and Grayson County. A heat pump handles both heating and cooling from a single unit and can be a good option when replacing aging single-purpose equipment.
Adon Complete in Denison
Owner Jesse Villarreal has over 27 years of HVAC experience. We are a Trane Comfort Specialist and Mitsubishi-authorized dealer, which means factory-trained technicians and the full manufacturer warranty on every system we install. We service all brands. We work in Denison regularly and know what the homes here need. Our technicians explain what they find before doing any work, and we don’t push repairs or replacements that aren’t warranted.
One of our Denison customers left a detailed review after our technician, Alex, repaired ductwork in her attic, explained every step of the process, and even helped her address a rodent issue that caused the duct damage. That is the standard we hold ourselves to on every call.
Serving Denison and Grayson County
We serve all of Denison, including Thompson Heights, the downtown historic district, and the neighborhoods along Highway 75. We also serve surrounding Grayson County communities, including Sherman, Van Alstyne, Pottsboro, Gordonville, and Whitesboro.
Questions Denison Homeowners Ask Us
My AC is running, but the house isn’t cooling down. What’s going on?
This is one of the most common calls we get in Denison. The system is running, but airflow is so restricted by dirty coils, a clogged filter, or blocked ductwork that it cannot transfer heat effectively. We have found systems in Denison cooling only 6 degrees when they should be cooling 18 to 20. A diagnostic visit will tell you exactly what is happening. Call (903) 482-4900 to schedule.
I have an older R-22 system. What are my options?
R-22 refrigerant is no longer being manufactured. If your system has a significant refrigerant leak, the practical answer in most cases is to replace it. We will tell you honestly when a repair makes sense and when it does not. If replacement is the right call, we will walk you through your options and give you a clear price before any work is done.
How do I know if my ductwork needs cleaning or repair?
Signs include uneven cooling between rooms, visible dust near supply vents, musty odors when the system runs, or a system that is working harder than it should. Our technicians have found disconnected ducts, rodent damage, and years of debris buildup in Denison homes during routine service calls. A professional duct cleaning and inspection is the only reliable way to know what is in there.
Do you offer HVAC maintenance plans in Denison?
Yes. Our Adon Care Club is $12 a month and includes two seasonal tune-ups, priority scheduling, repair discounts, no diagnostic fees, and 24/7 emergency access. For Denison homeowners with older systems, staying on a maintenance schedule is one of the best ways to catch small problems before they become expensive ones.
Do you offer emergency HVAC service in Denison?
Yes. We are available 24 hours a day, 7 days a week throughout Denison and Grayson County. When you call after hours, you reach a real person. Call (903) 482-4900 any time.
Schedule Heating and Air Conditioning Service in Denison
If your system hasn’t been serviced recently or you have noticed a change in performance, call Adon Complete Air Conditioning and Heating at (903) 482-4900 or schedule online. We know Denison, and we are ready to help.
Recent Jobs and Reviews in Denison, TX
Denison, TX at a glance
Adon Complete Air Conditioning and Heating has completed 10 jobs in Denison, TX between August 2026 and September 2026.
The 7 customer reviews shown here average 4.9 out of 5.
The most recent job was on September 17, 2026.
Adon Complete Air Conditioning and Heating has completed 91 jobs in Denison, TX in the last 12 months. The first job there was in March 2020.
Reviews
2nd tech to work on HVAC outage, was fixed however a bit of rainwater in the shorted the system. Quick service! Charles explained the remaining issue, which sounds as if it would have been hard to diagnose prior to the rain storm. Thank you!
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ALEX IS AMAZING! HE ARRIVED ON TIME, WAS EFFICIENT, KNOWLEDGABLE AND THOROUGH. HE WENT OUT OF HIS WAY TO PROVIDE EXCELLENT CUSTOMER SERVICE IN REPLACING DUCTS IN MY ATTIC, EXPLAINING EVERYTHING. AND EVEN HELPED ME CONTAIN THE RODENT PROBLEM THAT WAS RESPONSIBLE FOR THE PREVIOUS DUCT DAMAGE SINCE I WAS UNABLE TO CLIMB THE ATTIC LADDER MYSELF. HE WENT ABOVE AND BEYOND MY EXPECTATIONS. WHEN I HAVE ADDITIONAL DUCTWORK DONE -- HE WOULD BE MY CHOICE FOR A TECH. ALEX DESERVES A BIG RAISE!!! THANK YOU!
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5stars thank you charley
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He was there 10 minutes ahead of schedule and had us back up and running very quickly!
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I love this company. They Take great care of me
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Job Locations
Customer had concerns about water coming from soffit. Found that primary drain line was clogged and water was draining into secondary drain pan. Offered level 2 drain clearing to also remove water from pan, customer declined and only wanted drain line blown out. Cut and blew out drain line using nitrogen both directions. Poured water down drain line to verify it was clear. System is cooling at this time. There is a missing roof vent cap directly above system. It is not part of the HVAC system.
Arrive for 2 system AC maintenance. Checked filters, customer replaced them on his own. Set thermostats to cool and checked temperature drop across systems, both are achieving 19-20° difference. Checked operation of drain lines, they are clear and we treated both of them with drain solution. Next, went outside to condensers. Checked amp draw on compressors and fan motors. Starting amp draw on compressor for main house is above manufacturer limits and can lead to premature breakdowns. Recommend installing hard start kit to bring down the starting amps and prolong the life of the compressor. Both capacitors and contactors are good. Cleaned condenser coils using water. Both systems are cooling at this time.
Connected mantis tool to inverter board as directed by the instructions. Updated automatically loaded onto the board. Solid yellow light showed that update was installed successfully. Tested system after and system is cooling at this time.
No cool on single system. Customer stated that it was blowing out hot air as if it was in heating mode. Checked fault codes on thermostat and getting error 184.10 meaning Switch over valve is in incorrect position. After speaking with tech support, learned that it is a common problem with this unit and it just needs an update on the inverter drive outside. Office is looking into part for update. System is cooling at this time. Explained how to reset system in case it happens again before we come back out.
Return to the homeowners residence to install a replacement condenser fan motor. Removed the failed motor and installed the new condenser fan motor. Tested the HVAC system after installation and verified that the system is operating properly at this time. Also tested the primary drain line and verified that it is clear and draining properly.
Upon arrival which system and cooling mode and set the temperature down, I noticed that the indoor blower came on, so I went outside to check the condenser. I found condenser not running, so I checked the start capacitor, and the capacitor was good. When I reinstalled the start capacitor and turn the power back on at the disconnect, the compressor came on and the fan tried to come on, but is making a lot of noise. The fan will not spin. The fan motor on the condenser is seized up. I then got into the attic to check the drain line and drain line is clear. I left power off outside at the condenser. Homeowner may use thermostat and indoor unit for air circulation, but needs to keep the power turned off at the outdoor unit. We will need to schedule an install date for this fan motor.
No cool on single system. Customer stated that condenser sounded like it was running but the fan was not spinning. Checked capacitor and it had failed. Replaced capacitor under parts and labor warranty. Checked out system after repair. Measured amp draw on compressor and fan motor. System is cooling at this time.
Upon arrival, I found that the drain line was clogged, possibly causing the float switch to periodically trip. Tested and draws on blower, everything checked out good. Tested system several times and system is running properly at this time. Cleared drain line and tested drain. Drain line is clear.
Upon arrival I found the primary drain line was clogged, causing float switch to trip. I cleared drain line and restored power to system. System is running properly at this time.
Replaced blower motor under parts warranty. Tested system after repair. Previous fault code went away and system started cooling. Condenser coil was very dirty and blocking the airflow through the coils. Cleaned condenser using water only. Return air 84° supply 65°. System is cooling at this time.
