By Go Green Heating & Air Conditioning
Updated August, 2025 | 6-Minute Read
Keeping a home at the most comfortable temperature can often be taken for granted. Everybody expects their air conditioning unit to continue working properly, and they go about their daily routines without so much as thinking about it. That is, of course, until something changes. When you notice your AC is not cooling, yet it’s still running, something is likely amiss within your system.
Whether it’s simply a minor issue or something more drastic, you want it resolved quickly. It’s important to identify what’s causing the issue, but it’s just as important to let a professional HVAC technician diagnose any complex problems that require AC repair in Denver. Regular maintenance can help prevent a lot of these issues, but there are a number of things that can impact the efficiency of your system.
Is Your Air Conditioner Not Cooling?
Is your air conditioner running but not cooling? Here are four reasons why that may be:
1. Clogged Air Filters
One of the biggest culprits for hurting the efficiency of your air conditioning system is the filter. When the air filter becomes dirty or clogged, airflow is restricted. That reduces the efficiency of the overall system. Regularly changing or cleaning the air filter is critical for optimal performance from your system. This should be the first thing you check when investigating your system’s efficiency, and inspecting this regularly will give insight into how often it should be replaced.
2. Dirty or Blocked Coils & Drains
As time passes, the coils on the evaporator and condenser units can accumulate dirt and other debris. This reduces their efficiency, meaning regular cleaning is necessary to maintain the best heat exchange. Also, if the condensate drain becomes clogged, it can lead to water buildup and impact the system’s ability to cool the air. Regular maintenance and inspections on both of these items can prevent both of these issues.
3. Electrical Problems
Faulty wiring or constantly tripping breakers can mess with the electrical system of the air conditioning unit, leading to inefficient cooling or other issues. Electrical issues at the thermostat can also cause it to malfunction, which can make the AC not cool your space adequately. During your regular inspections, the technician should be able to identify some of these problems, and electrical issues should always be addressed immediately.
4. Bad or Leaky Insulation
Poor insulation in your structure can cause the conditioned air to escape, impacting its efficiency. Leaks in the ductwork can create a similar problem. This loss of the cooled air will reduce the overall efficiency of your system. Not only does this cause issues with keeping your space at the right temperature, but it can also result in higher energy bills while your system works that much harder to cool the area.
How to Troubleshoot Your AC
Before calling a professional, you can perform a few simple checks that might help you pinpoint the cause of your AC running but not cooling:
- Check the Thermostat Settings: Make sure that your thermostat is set to “cool” and the temperature is set below the current room temperature. Sometimes settings change accidentally, and the unit will run without cooling effectively.
- Inspect the Air Filter: A dirty or clogged air filter restricts airflow. Replace or clean your filter regularly to keep air flowing.
- Examine the Outdoor Condenser Unit: Make sure the outdoor unit isn’t blocked by debris, leaves, or plants. If it is, gently clear away anything blocking it.
- Look for Frozen Coils: If you notice ice on the indoor evaporator coil, it may indicate restricted airflow or low refrigerant levels. Turn off your unit, allow it to thaw, then call a technician for a thorough check.
- Verify Power Supply and Breakers: Check that your AC has power and no breakers have tripped.
- Close Unused Vents Cautiously: Closing too many vents can increase pressure and reduce cooling efforts. Ensure vents are open where airflow is needed.
If these steps don’t resolve the issue or if you’re uncomfortable performing any of the above troubleshooting tactics, it’s best to contact an HVAC technician.
Air Conditioner Repairs & Ongoing Maintenance Checks
Most of these issues can be fixed with repairs or prevented through regular maintenance by an HVAC contractor, while some problems may simply arise due to age and normal wear over time. Regular inspections will be less expensive in the long run, may extend the lifespan of your unit, and ultimately keep your home at the comfort level you desire. For more information on how to keep your AC running optimally and efficiently, contact the experts at Go Green Heating & Air Conditioning today online or by calling 303-731-4417.
About the Author
Denver Heating & Air Conditioning has served homeowners throughout the Denver metro area with professional HVAC installation, repair, and maintenance services for over 20 years. Our team includes NATE-certified technicians who specialize in indoor comfort solutions, energy efficiency, and whole-home air quality.
