The statement that air conditioners are more than 100% efficient is a misconception or misinterpretation of certain technical terms related to energy efficiency. In reality, air conditioners, like all other machines, cannot have an efficiency greater than 100%.
Efficiency is a measure of how well a device converts energy input into useful output work. In the case of air conditioners, it is about how efficiently they can remove heat from indoor air and cool down the environment.
The confusion might arise due to the coefficient of performance (COP), which is commonly used to describe the efficiency of refrigeration and air conditioning systems. COP is defined as the ratio of cooling (or heating) output to the energy input:
COP = Cooling Output (in watts) / Energy Input (in watts)
The COP can be greater than 1, and it's often expressed as a ratio like 3:1, 4:1, etc. For instance, a COP of 3:1 means the air conditioner produces three times more cooling energy than the electrical energy it consumes.
However, it's essential to understand that COP doesn't represent efficiency in the traditional sense because it doesn't take into account the total energy used, including the energy lost as waste heat during the cooling process. The energy input remains greater than the cooling output, but the COP indicates how effectively the air conditioner transfers heat.
In practical terms, the higher the COP, the more efficient the air conditioner is at cooling. Modern air conditioners can achieve relatively high COP values, making them more energy-efficient and environmentally friendly compared to older models. But again, their efficiency is always less than 100%.