EER (Energy Efficiency Ratio) another measure of your air conditioner’s energy efficiency
Sometimes cooling devices such as central air conditioning systems are rated using EER (Energy Efficiency Ratio) versus SEER (Seasonal Energy Efficiency Ratio).  EER is a measure of how efficiently an air conditioner will operate when the temperature outside is at a specific level – the higher the EER, the higher the efficiency of the unit.  The main difference between the two measurements is that EER measures efficiency at peak day operations while SEER measures efficiency over the entire cooling season.