The Seasonal Energy Efficiency Ratio (SEER) is an energy efficiency rating for air conditioners. This is the cooling output provided by the unit during normal annual usage period, divided by its total energy consumption. The higher the SEER, the better the energy performance, the more you save. The DOE's established minimum SEER rating for cooling is 13.00. Rating is only applicable to units under 6 tons (65,000 Btu/H).