Energy Efficiency Ratio (EER)
EER is is a term to define cooling efficiencies of chillers, unitary air-conditioning and heat pump systems.
The EER of a particular air conditioner is calculated by dividing the amount of cooling created (BTU) by that above equipment under a single set of conditions by the input electrical power in Watt (W) to operate that equipment. Typically, the condition for calculating EER is an outdoor temperature of 95°F and indoor temperature of 80°F with 50% humidity.
EER = BTU / W
Higher EER means more efficient system.
EER = 12 / (KW/ton)
If a chillers efficiency is rated at 1 KW/ton, the EER equals 12 (EER=12).
Seasonal Energy Efficiency Ratio (SEER)
SEER is the cooling output of above equipment for a typical cooling season divided by the total electric energy input for that equipment operation during the same time frame. SEER is calculated using a range of outside temperatures ranging from 65°F to 104°F.
Higher SEER rating means greater energy efficiency.