What is the Difference between Seer and Seer2 Ratings in 2026?

The primary difference between SEER and SEER2 ratings in 2026 relates to the mandatory efficiency standards and testing protocols required for new HVAC installations in Canada. Starting January 1, 2026, all newly installed central air conditioners and heat pumps must meet a minimum efficiency of at least 14.0 SEER2.

Key differences include:

• Testing Methodology: The older SEER standard used the A2 test, while SEER2 utilizes the more rigorous M1 testing procedure. This new method accounts for higher external static pressure and blower heat to better simulate real-world ductwork and installation conditions.
• Rating Values: Because the M1 test is more demanding, a unit’s SEER2 number is typically lower than its original SEER rating, even though the actual efficiency of the equipment remains the same.
• Conversion Factor: To compare older SEER units to the new standard, a conversion factor is used. While it varies by equipment, the official factor is approximately 0.9. This means a unit previously rated at 15.5 SEER provides energy savings comparable to a 14.0 SEER2 model.
• Regulatory Requirements: According to Natural Resources Canada (NRCan), the 2026 mandate only applies to new installations. Homeowners with existing SEER-rated systems are not required to upgrade until they choose to replace their equipment.

• SEER2 vs SEER Rating Explained: Complete Guide for Homeowners