What aspect of an air conditioning system can be negatively affected if there is too much refrigerant?

An excess of refrigerant in an air conditioning system can indeed have a significant impact on the cooling efficiency. When there is too much refrigerant, it can lead to a condition known as "flooding," where the compressor receives liquid refrigerant instead of vapor. This situation can prevent the compressor from operating efficiently, resulting in reduced cooling performance. As the system struggles to maintain the desired temperature, it becomes less efficient, leading to possible failures in reaching the setpoint temperature.

In addition to cooling efficiency, overcharging the system with refrigerant can also cause strain on the compressor, leading to potential damage and impacting its lifespan, as well as affecting condenser performance due to improper heat exchange. However, the primary and most immediate effect of having an excessive amount of refrigerant is the negative influence on cooling efficiency, which is why this answer correctly highlights one of the critical consequences of incorrect refrigerant levels in an AC system.