SEER vs SEER2: What’s the Difference?

2 minute read • Last update July 2024

graham lumley
Written by: Graham Lumley
heat pump system

In this article

    What’s the difference between SEER and SEER2?

    SEER and SEER2 are both measurements of the efficiency of an HVAC (heating and cooling) system. SEER2 is an updated, more accurate methodology that was introduced as the new standard in 2023.

    The SEER2 measurement system better reflects real-world conditions and as a result the SEER2 rating of an HVAC system such as an air conditioner or heat pump will be lower than its SEER rating.

    What is SEER?

    SEER stands for Seasonal Energy Efficiency Ratio. It measures the energy efficiency of an HVAC system’s cooling abilities by dividing the cooling output of the air conditioner over a typical cooling season by the energy used in watt hours. The higher the SEER rating, the more efficient the cooling system.

    What is SEER2?

    SEER2 is the new standard of HVAC energy efficiency measurement. It is more accurate than SEER because it resembles more realistic operating conditions of a system during the measurement process.

    By adjusting the external static pressure during the test from 0.5 inches of external water column pressure down to 0.1 inches, the rating is more accurate. This also means that SEER2 ratings will be lower than SEER ratings for the same system.

    What this change means for homeowners

    The switch from SEER to SEER2 implemented by the U.S. Department of Energy in 2023 has forever changed the way HVAC systems are manufactured, sold, and installed across the country.

    As of January 1, 2023, there are new required minimums for SEER and SEER2 ratings. If a system does not meet those requirements, it cannot be installed on a home. As a result, this means that the systems that are being manufactured must meet certain requirements and older uninstalled systems that do not meet those requirements are rendered obsolete.

    Here are the new minimum requirements by region:

    Southeast RegionSEERSEER2
    Air Conditioning System15.014.3
    Heat Pump15.014.3
    Source: https://seer2.com/region-southeast.html
    Southwest RegionSEERSEER2
    Air Conditioning System15.014.3
    Heat Pump15.014.3
    Source: https://seer2.com/region-southwest.html
    North RegionSEERSEER2
    Air Conditioning System14.013.4
    Heat Pump15.014.3
    Source: https://seer2.com/region-north.html

    Written by Graham Lumley

    Graham Lumley, Digital Marketing Manager at BKV Energy, leads digital and traditional marketing strategies, focusing on educating Texans about the state's deregulated energy market. With over 8 years of marketing experience, he creates content to help consumers understand and save on their energy bills, bringing a fresh and dynamic approach to the industry.

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