If your AC unit is working but not blowing cold air, you’re not alone. It’s one of the most common AC problems Colorado homeowners face, especially during peak summer heat. Your air conditioning system might be running continuously, yet your home still feels warm and uncomfortable. This issue can stem from several factors, including a dirty air filter, a faulty thermostat, refrigerant leaks, or blocked evaporator or condenser coils.
At Van Genderen Heating & Air Conditioning, we specialize in diagnosing and resolving these issues promptly. Let’s walk through the most likely causes and how you can address them, starting with a bit of HVAC troubleshooting.
Common Reasons Your AC Is Running But Not Cooling
1. Clogged or Dirty Air Filter
A clogged air filter restricts airflow, significantly reducing system efficiency. This can cause your air conditioner not to blow cold air but still run, resulting in higher electricity use and worsening indoor air quality.
Fix: Replace or clean your air filters monthly to maintain optimal ventilation, reduce strain on your air handler, and avoid poor airflow. Please use a Merv 8 or lower, not a higher Merv filter.
2. Refrigerant Leaks or Low Levels
Your AC relies on refrigerant to cool the air. If you have a leaking AC unit or were undercharged during installation, your system can’t complete the heat exchange process needed to cool your home effectively.
Fix: Only a licensed HVAC technician should test pressure, repair leaks, and recharge refrigerant to the manufacturer’s specifications.
3. Dirty Condenser or Evaporator Coils
The condenser (outside) and evaporator coil (inside) are essential components of the air conditioning system. Dirt, plants/vines, or buildup on these parts interferes with airflow and cooling.
Fix: Keep the condenser area clear. During a scheduled service, our team cleans these coils to restore system function and seasonal energy efficiency ratio (SEER) performance.
4. Thermostat Issues
A thermostat not working or improperly calibrated can result in incorrect temperature readings, causing the AC to run without adequately cooling.
Fix: Verify settings are on “cool” and at a lower temperature than the current room reading. If problems persist, a smart thermostat upgrade can help manage climate and humidity more efficiently.
5. Blocked or Leaky Ductwork
If your central AC is not cooling, the problem could be hidden in your walls or attic. Leaks, cracks, or clogged ducts mean cold air isn’t reaching your living spaces.
Fix: Let our technicians inspect your registers to make sure they are all open and we don’t see any hidden blockages.
6. Compressor or Mechanical Failures
The compressor is the engine of your AC system. If it fails, your unit may hum but not blow cold air. Likewise, if your fan is running but not cooling, it may indicate a problem with the air handler or blower assembly.
Fix: Professional air conditioning service is required to diagnose mechanical issues, test for short cycling, and ensure your system is running safely.
7. Drainage and Circuit Breaker Issues
A blocked drain line or tripped circuit breaker can cause your air conditioning system to power on but not function correctly.
Fix: Reset breakers if needed and ensure your drainage system is clean to prevent water damage and high humidity levels that encourage mold and odor issues.
When to Call a Professional?
While some AC troubleshooting steps—like checking your air filter or clearing debris—are DIY-friendly, deeper problems require an expert’s eye. Whether it’s a leaking AC unit, a strange noise, or complete system failure, attempting repairs yourself can void your warranty or cause further damage.
At Van Genderen, our certified HVAC professionals use the latest home automation and diagnostic technology to accurately identify issues and deliver long-term solutions.
FAQs About Why Isn’t My AC Cooling?
1. What should I check first if my AC is running but not cooling?
Start with the air filter, thermostat, and outdoor condenser unit. These are the most common culprits behind reduced cooling.
2. Can humidity affect how my AC cools?
Yes. High humidity reduces comfort and strains your system. Make sure your humidifier is shut off and the door and windows are shut.
3. How do I know if I have a refrigerant leak?
Signs include ice buildup on coils, AC blowing cold air outside and warm air inside, or a faint hissing sound. A technician can confirm with pressure testing. Van Genderen still carries the older R22/Freon as well as R410A Puron and the new types.
4. Could climate change impact my AC system?
Absolutely. As climate patterns shift, systems are under greater strain. Upgrading to an Energy Star®-certified model helps reduce your carbon footprint and adapts to rising heat loads.
5. Is it worth repairing an older AC unit?
If your unit is over 15 years old and frequently has problems, replacing it with a high-efficiency furnace and AC unit is recommended.
Schedule Service with Van Genderen Heating & Air Conditioning
If your AC stopped working suddenly, your AC fan is not working, or your AC is working but not cooling, don’t wait for the problem to escalate. Van Genderen Heating & Air Conditioning has proudly served Centennial, Highlands Ranch, Denver, Parker, Castle Rock, and surrounding areas for over 75 years.
We handle all air conditioning repairs, installations, and seasonal maintenance to keep your system operating efficiently and reliably. At Van Genderen Heating & Air Conditioning, we proudly serve multiple areas across Colorado. Whether you need AC repair in Highlands Ranch, Lone Tree, or Castle Rock, our experienced HVAC technicians are ready to help. We offer fast, reliable service to keep your home cool and comfortable all summer long.
Call us today at (303) 744-2776 or schedule service online. Let’s get your air conditioning system back to blowing cold air—just in time for Colorado’s summer heat.
