SEER vs SEER2 Rating Explained: What HVAC Buyers Need to Know

When shopping for air conditioners or heat pumps, understanding efficiency ratings is key to making an informed choice. At HVACProSales.com, we want to ensure both HVAC contractors and homeowners know exactly what SEER and SEER2 ratings mean, the recent changes introduced by the Department of Energy (DOE), and how these updates impact your purchase decisions.

What is SEER? Understanding Seasonal Energy Efficiency Ratio

SEER stands for Seasonal Energy Efficiency Ratio. It measures the cooling output of an air conditioner or heat pump over a typical cooling season, divided by the energy consumed in watt-hours. The higher the SEER rating, the more energy-efficient the system is, which translates to lower electricity bills and reduced environmental impact.

For years, SEER has been the industry standard to compare unit efficiencies. For example, a unit with a SEER of 16 is more efficient than one with a SEER of 13.

Why Did the DOE Introduce SEER2 in 2023?

Starting in 2023, the DOE implemented a new test procedure known as M1, which more accurately reflects real-world installation conditions. This change led to the introduction of the SEER2 rating, which replaces the traditional SEER metric for federal efficiency standards.

The M1 test accounts for factors such as typical duct losses and outdoor fan power, which were underestimated in the previous test. Because of this, SEER2 ratings are generally slightly lower than SEER ratings for the same unit.

How to Convert SEER to SEER2

To estimate SEER2 from a known SEER rating, multiply the SEER value by 0.95. For example:

• A 16 SEER unit converts to approximately 15.2 SEER2 (16 × 0.95 = 15.2)
• A 20 SEER unit converts to approximately 19 SEER2 (20 × 0.95 = 19)

This conversion helps buyers and contractors understand how older SEER ratings compare to the new SEER2 standard.

Minimum Efficiency Standards by Region

The DOE has updated minimum efficiency requirements to reflect the new SEER2 ratings. These vary by region across the U.S. based on climate zones.

Region	Minimum Efficiency (SEER2)	Previous Minimum (SEER)
North (Cooler Climates)	13 SEER2	13 SEER
South (Warmer Climates)	14 SEER2	14 SEER

These standards ensure HVAC systems meet regional energy efficiency needs, helping reduce energy waste and save consumers money.

What Does This Mean for HVAC Buyers?

For homeowners and contractors purchasing HVAC equipment through HVACProSales.com, understanding SEER2 means:

• Expect slightly lower efficiency numbers due to the updated test procedure — this does not mean your system is less efficient, just tested differently.
• Be sure to verify SEER2 ratings on product spec sheets to comply with current federal and state regulations.
• Consider choosing high-efficiency models that exceed minimum SEER2 standards to maximize savings and comfort.
• Ask your HVAC contractor about the new test procedure and how it affects equipment selection.

MRCOOL SEER2 Ratings: High Efficiency You Can Trust

MRCOOL is a trusted brand featured on HVACProSales.com, known for innovative mini-splits and HVAC solutions. Their units comply with the new SEER2 testing and offer excellent energy efficiency.

For example, many MRCOOL mini-split models achieve SEER2 ratings ranging from 16 to 21, ensuring they meet or exceed regional efficiency requirements. You can explore these models directly on our MRCOOL Mini Split page.

Explore Related Products

• Complete HVAC Systems – including units with updated SEER2 ratings
• HVAC Tools & Accessories – essential for contractors working with new standards

SEER vs SEER2: Quick Comparison Table

Aspect	SEER	SEER2
Test Procedure	Old DOE test (pre-2023)	New DOE M1 test (2023+)
Efficiency Number	Usually slightly higher	Approximately 5% lower (multiply SEER × 0.95)
Includes Duct Losses	No	Yes
Minimum Federal Standard (South)	14 SEER