When the time comes to replace your home’s air conditioning system, you’ll encounter a new language of acronyms like SEER and SEER2. Understanding these terms is the key to making a smart financial and energy-efficient decision, especially in the Arizona climate where an AC unit is a home's most important appliance.

A Simple Explanation: SEER vs. SEER2

SEER stands for Seasonal Energy Efficiency Ratio. Think of it like the miles-per-gallon rating on a car. A higher SEER rating means a system delivers more cooling output for every dollar you spend on electricity. In short, the higher the SEER, the less energy your AC needs to keep your home comfortable.  

In 2023, the Department of Energy (DOE) implemented new regulations and changed the way AC systems are rated, introducing a new standard called SEER2. The main difference between SEER and SEER2 is the testing method. While the original SEER standard was based on ideal lab conditions, SEER2 uses more realistic testing procedures that account for factors like a home’s ductwork and static pressure. This means a SEER2 rating is a more accurate reflection of how a system will perform in your actual home.  

The New Arizona Standards

Arizona is part of the Southwest regional standard for AC efficiency, which has some of the strictest requirements in the country. As of January 1, 2023, all new air conditioners and heat pumps installed in Arizona must meet the new minimum SEER2 ratings.  

Here is a breakdown of the new minimum requirements for residential systems :  

• Split system ACs (under 45,000 BTU/h): Minimum 14.3 SEER2
• Split system ACs (over 45,000 BTU/h): Minimum 13.8 SEER2
• Packaged units: Minimum 13.4 SEER2
• Heat pumps (all sizes): Minimum 14.3 SEER2

Why a Higher SEER2 Rating Matters

You may see units available with SEER2 ratings of 16, 18, or even higher, which often come with a greater upfront cost. While a 14.3 SEER2 unit meets the minimum requirement, choosing a higher-rated system is a wise long-term investment.  

For example, a 16 SEER2 unit uses roughly 12 to 13 percent less energy than a 14 SEER2 unit to provide the same amount of cooling. For an Arizona homeowner, where AC is the single largest energy expense, this difference can lead to substantial savings on every utility bill, helping the more expensive unit pay for itself over time.  

Additionally, higher-rated units often feature advanced technologies like variable-speed compressors. This allows the system to run longer at lower speeds, which provides more consistent temperatures, better humidity removal, and fewer jarring temperature swings. By choosing a system with a higher SEER2 rating, you are not only saving money on energy costs, but also investing in a more comfortable and reliable home.