If your air conditioner is no longer blowing cold air after leaving a window open for 20 minutes, there are a few possible reasons for this issue:
Heat Infiltration: When you leave a window open, warm air from outside can enter your living space. This can increase the indoor temperature and put a strain on your air conditioner, making it harder for it to cool the air effectively.
Thermostat Confusion: If your air conditioner has a thermostat that senses indoor temperatures, the sudden influx of warm air from the open window might cause the thermostat to register a higher temperature than it actually is. As a result, the AC may not run as frequently or may shut off prematurely, leading to less cooling.
Airflow Obstruction: Leaving the window open may also cause curtains, blinds, or other objects to obstruct the airflow from the AC vents. Reduced airflow can prevent cold air from reaching the intended areas and result in less effective cooling.
Refrigerant Issues: Your air conditioner's cooling capability relies on a refrigerant that absorbs heat from indoor air and releases it outside. If there is a refrigerant leak or a problem with the system's refrigerant levels, the AC may struggle to cool the air properly.
Overworking the Compressor: The sudden increase in indoor temperature due to the open window can lead to the compressor working harder to maintain the desired cooling level. Over time, this increased workload can cause strain on the compressor and affect the AC's performance.
To address the issue, try the following steps:
Close the Window: Start by closing the window to prevent further heat infiltration and give the air conditioner a chance to cool the indoor air effectively.
Check Airflow: Ensure that no objects are obstructing the airflow from the AC vents, and make sure they are fully open and unobstructed.
Allow Time to Recover: Give the air conditioner some time to recover from the increased heat load. It may take a while for it to bring the indoor temperature back to the desired level.
Check Refrigerant Levels: If the problem persists, contact a professional HVAC technician to inspect your air conditioning system for any refrigerant leaks or other issues that may be affecting its cooling performance.
By addressing these potential issues, you can improve your AC's cooling efficiency and maintain a comfortable indoor environment.