What's the Difference Between EER and SEER Ratings? – Sobieski Services | DE, NJ, PA, MD

What’s the Difference Between EER and SEER Ratings?

Air conditioning systems cool a home using very cold refrigerant to remove heat from airflow. When you’re shopping for a new or replacement air conditioner, you probably want to know how efficient any given system will cool your home to make an educated decision for system selection. That’s where EER and SEER ratings factor into the equation.


Ratings EER and SEER are acronyms for the energy efficiency ratio and seasonal energy efficiency ratio respectively. These cooling efficiency ratings are displayed on the bright yellow EnergyGuide label and likely included in an air conditioner’s description on HVAC websites and literature. Here’s what these terms mean:

  • The EER rating represents how efficient an air conditioner operates in a steady-state environment — the same continuous temperature, which is 95 degrees. In technical jargon, EER calculation is heat removal capacity in BTUs divided by energy input in watts — BTU/watt-hours.
  • The SEER rating represents how efficient an air conditioner operates during the entire cooling season at varying simulated environmental temperatures. The calculation is the same as EER — BTU/watt-hours.

Ratings and Lifetime Costs

  • Air conditioners available today can deliver as high as 26 SEER. That’s more than double the efficiency of old systems. To make sense of all the efficiency rating numbers, ask your HVAC technician to perform a lifetime cost analysis and return on investment (ROI) of systems you’re considering. SEER ratings are generally used to measure the efficiency of central air conditioners and used for lifetime and ROI calculations.
  • The lifetime cost analysis factors purchase price, estimated operating expenses, estimated repairs and maintenance for the life span of the system — your total investment.
  • The ROI shows when energy savings of a higher-efficiency air conditioner pays the difference of the higher purchase price. Your household’s average air conditioning usage is used for the calculation for results specific to your needs.

At Sobieski Services, Inc., our goal is to help our customers in Delaware, Pennsylvania, Maryland and New Jersey learn more about energy and home comfort issues – especially HVAC and plumbing issues – so that they can save money and live in healthier, more comfortable homes.

Photo Credit: Jan Tik via Compfight cc

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