The answer to 'why is my furnace not cooling' is that the most common causes are a malfunctioning air conditioning unit, low refrigerant levels, or a blocked air filter. Symptoms may include warm air blowing from the vents, the furnace running continuously, and high energy bills.
Some potential solutions are to check and replace the air filter, inspect the outdoor condenser unit for debris or damage, and ensure the refrigerant levels are adequate. If the issue persists, it's best to call a professional HVAC technician to diagnose and repair the problem.