Ans: The EER rating is calculated by dividing cooling capacity/ power consumption. So, all you need to do to find out the energy efficiency is that the higher the EER the better efficiency an AC has in terms of energy consumption.  You can also use this formula to find out the power consumption or the cooling capacity individually. EER= cooling capacity in BTU/ power consumption in Watts                                          or Cooling capacity = power consumption X EER                                Or Power consumption = Cooling capacity/EER