SEER vs SEER2: What's the Difference?

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 Region	SEER	SEER2
Air Conditioning System	15.0	14.3
Heat Pump	15.0	14.3

Source: https://seer2.com/region-southeast.html

Southwest Region	SEER	SEER2
Air Conditioning System	15.0	14.3
Heat Pump	15.0	14.3

Source: https://seer2.com/region-southwest.html

North Region	SEER	SEER2
Air Conditioning System	14.0	13.4
Heat Pump	15.0	14.3

Source: https://seer2.com/region-north.html

Written by Graham Lumley

Graham Lumley is the Growth Product Manager at BKV Energy, a retail electricity provider in Texas' deregulated market, where he has worked since 2023. He analyzes customer usage and billing data, helps develop BKV's fixed-rate plans, and creates tools to simplify Texas electricity shopping. He has written over 200 articles on Texas electricity rates, delivery charges, plan types, energy generation, and more to help Texans understand their bills and pay less. With over 10 years of experience in consumer products, marketing, and energy, he explains the Texas electricity market in plain language.