The answer to 'why is my central air not cooling' is that there are several common causes, such as a refrigerant leak, a problem with the compressor, or a clogged air filter. Symptoms may include the air not feeling cold, the system running constantly, or warm air blowing from the vents.
Some issues, like a dirty air filter or low refrigerant, can be addressed with basic DIY maintenance. However, more complex problems like a compressor failure or major refrigerant leak will likely require a professional HVAC technician to diagnose and repair. It's important to address the issue promptly to avoid further damage to the system and prevent a complete breakdown.