A lack of refrigerant in the system: A lack of refrigerant forces the system to work harder to generate cold air. Because air conditioning systems do not consume or burn refrigerant, a low level indicates either a leak or insufficient filling at the time of installation.

Grime and dirt on the condenser coil: Dust, dirt, and grime can accumulate and become caked onto the condenser coil of your air conditioner. When a layer of dirt covers the condenser coil, it makes it more difficult for the refrigerant inside the coil to condense back to liquid form, making the system far less effective.

Blocked air conditioning drain tube: Condensation naturally occurs when warm air meets cold evaporator coils. The water that has accumulated is collected in a drip pan and drained away from the system. If that drain line becomes clogged, water can back up into the system, covering the evaporator coil in ice and causing the entire system to malfunction.

Faulty sensors or electrical controls: The air conditioning system’s compressor and fan rely on the flow of electrical current to function. The air conditioning system will no longer function properly if a faulty electrical control interrupts the flow of power. The system also relies on sensors inside the thermostat to determine when to turn on and off. A faulty thermostat sensor could cause the air conditioning system to run continuously or not at all.