- In technical terms, SEER is a measurement of the total cooling of a central air conditioner or heat pump (in BTUs) during the normal cooling season as compared to the total electric energy input (in watt-hours) consumed during the same period Energy Efficiency Ratio
Energy Efficiency Rating (EER) is a measure of how efficiently a cooling system will operate when the outdoor temperature is at a specific level (95oF). The higher the EER, the more efficient the system.
- In technical terms, EER is the steady-state rate of the removal of heat energy (i.e. cooling capacity) by the product measured in Btuh divided by the steady-state rate of energy input to the product measured in watts. This ratio is expressed in Btuh/watt.
Both SEER and EER are detailed in ENERGY STAR specifications because each rating indicates the energy efficiency of the product under different operating modes. SEER rating more accurately reflects overall system efficiency on a seasonal basis and EER reflects the system’s energy efficiency at peak day operations. Both ratings are important when choosing a product.