What’s an EER?

What’s an EER?

An air conditioner's efficiency is measured using the Energy Efficiency Ratio (EER) for cooling and Coefficient of Performance (COP) for heating.
Energy Efficiency Ratio (EER), also commonly expressed as Energy Efficiency Rating, gives you an insight about how much cooling capacity the unit provides from a specific amount of energy used. 
Every air conditioner is assigned with a specific EER. It is expressed in values or number. 
The EER of an air conditioner is the ratio derived from dividing the cooling output of a unit (expressed in British thermal units per hour or Btu) with the energy input in watts.