What is the relationship between energy efficiency and power factor?

Energy efficiency (energy efficiency ratio) is not directly related to power factor. Energy efficiency refers to the ratio of output energy to input energy. Due to the conversion loss, the output energy of general equipment is often less than the input energy, so the energy efficiency ratio is less than 1. However, some equipment (such as air conditioning) has a higher energy efficiency ratio, which can reach more than 3 because of its special working principle. Power factor (cosφ) refers to the ratio of active power to apparent power. Because the active power cannot be greater than the apparent power, the maximum power factor is only 1, and the range of power factor is consistent with the definition domain of COS function.