Understanding the Difference Between SEER and SEER2

Understanding the Difference Between SEER and SEER2

     When shopping for an air conditioner or heat pump, you’ve probably encountered the terms SEER (Seasonal Energy Efficiency Ratio) and SEER2. Both are used to measure the energy efficiency of HVAC systems, but there’s a key difference between them, which can affect both the performance of your unit and your energy bills. Here’s a breakdown of what each term means and how they differ.

What is SEER?

     SEER stands for Seasonal Energy Efficiency Ratio. It is a metric that measures the efficiency of an air conditioning system or heat pump over a typical cooling season. SEER is calculated by dividing the total cooling output (measured in BTUs) by the total energy input (measured in watt-hours) over a typical cooling season. The higher the SEER rating, the more energy-efficient the system is.

For example, an air conditioner with a SEER rating of 16 will be more energy-efficient than one with a SEER rating of 13. Generally, the higher the SEER, the lower the operating cost, as it consumes less energy to cool your space.

What is SEER2?

     SEER2 is an updated version of the SEER rating introduced by the U.S. Department of Energy (DOE) in 2023. SEER2 is similar to SEER in that it still measures the cooling efficiency of HVAC systems, but the testing procedures and conditions have changed to better reflect real-world performance.

     The primary difference between SEER and SEER2 lies in the way the tests are conducted. SEER2 requires the unit to be tested under more stringent conditions, including the use of more realistic air flow rates and temperature settings. This means that SEER2 ratings tend to be lower than SEER ratings for the same unit, but they are considered more accurate in terms of how the system will perform in actual conditions.

Why the Change?

     The shift from SEER to SEER2 was made to better align energy efficiency standards with current technology and actual usage scenarios. SEER2 also accounts for new regulations and higher standards for refrigerants, which are more environmentally friendly but often require more energy to operate.  Below is a table showing what an old SEER rating would be using the new SEER2 rating.  

The Bottom Line

     If you’re in the market for a new HVAC system, understanding the difference between SEER and SEER2 is essential. While SEER ratings are still in use for older models, newer units will likely be labeled with SEER2 ratings, which provide a more realistic assessment of energy efficiency. Choosing a higher SEER2-rated system will help reduce your energy consumption, lower your utility bills, and ensure you’re complying with modern efficiency standards.