The answer to 'why is my evaporator coil not cooling' is that the evaporator coil is likely not functioning properly. This can be caused by a few common issues, such as a refrigerant leak, a blocked airflow, or a problem with the blower fan. The evaporator coil is responsible for absorbing heat from the air in your home, and if it's not working correctly, you won't feel the cooling effect.
Some common symptoms of an evaporator coil issue include warm air coming from your vents, high humidity in your home, and ice buildup on the coil itself. To troubleshoot the problem, you'll need to check the refrigerant levels, inspect the coil for debris or blockages, and ensure the blower fan is working properly. If you're not comfortable doing this yourself, it's best to call a professional HVAC technician to diagnose and repair the issue.