EER

EER stands for Energy Efficiency Ratio.

Like SEER, the Energy Efficiency Ratio (EER) of a cooling unit is determined by the output cooling divided by the electrical power input. As opposed to SEER which is calculated over a range of outside temperatures, EER is typically determined by a set outside air temperature, a set inside air temperature and a 50% relative humidity. For a comparison point, 11 EER is roughly equivalent to 13 SEER.