Understanding AC efficiency? Let’s break down the ratings: EER measures an air conditioner’s efficiency at a specific temperature (usually 95°F) and is typically between 8 to 12. SEER, or Seasonal Energy Efficiency Ratio, shows overall cooling efficiency over a season, ranging from 13 to 25, with higher numbers indicating better efficiency. SEER2 is a newer, stricter rating that accounts for real-world conditions like higher outdoor temperatures and resistance from ductwork, resulting in slightl