What is the Difference between Seer and Seer2?

Aug 3, 2026

The primary difference between SEER and SEER2 lies in the testing procedures used to measure energy efficiency. While both metrics measure the Seasonal Energy Efficiency Ratio, SEER2 was introduced in January 2023 to provide a more accurate, real-world representation of a system’s performance.

Key differences include:

  • Testing Conditions: The older SEER standard used a testing pressure of 0.1 inches of water column (in. w.c.). The updated SEER2 standard uses the more rigorous M1 blower test, which increases the external static pressure to 0.5 in. w.c.
  • Real-World Realism: This higher pressure better simulates the actual resistance airflow faces in a home’s ductwork and filters. Because the SEER2 test is more “honest” and difficult, the same unit will typically have a SEER2 rating that is one to two points lower than its original SEER rating (for example, a 16 SEER unit might be rated as 15.2 SEER2).
  • Regulatory Status: SEER2 is the current federal standard for all new air conditioners and heat pumps manufactured as of 2023. While older SEER systems are grandfathered in, all modern performance standards and federal mandates are now measured using SEER2.

Related FAQs

chat-icon

Offer Title

Text here...

Request more info

Complete the form below and our team will contact you as soon as possible. If you want to talk to us now, call 719-505-2027

Offer Disclosure