With the San Joaquin Valley’s blazing summer nearly upon us, if you’re looking for an air conditioning upgrade, you’ll need to know how to compare the energy efficiency of different models. Most people think the SEER (seasonal energy efficiency ratio) is the best way to make a comparison. But increasingly, in climates with hot summers, EER is becoming the better standard for comparison. So when it comes to SEER versus EER, go with the latter number.