Understanding SEER2: What the New AC Efficiency Rating Means for You

If you've shopped for an air conditioner recently, you've seen the term SEER2. It replaced the older SEER rating in 2023, and understanding it helps you compare systems and estimate your cooling costs.

What does SEER2 measure?

SEER2 stands for Seasonal Energy Efficiency Ratio 2. It measures how efficiently an air conditioner or heat pump cools over a typical season, factoring in real-world conditions like cycling and duct pressure. Higher SEER2 means more cooling output per unit of electricity — and lower energy bills.

SEER vs. SEER2: what changed?

The new test conditions are stricter, so a SEER2 number is roughly 4 to 5 percent lower than the old SEER number for the same equipment. That means a 14 SEER2 system is more efficient than an older 14 SEER unit was. Don't compare the two numbers directly.

Minimum efficiency by region

In the northern US, the minimum for central ACs is 13.4 SEER2; in the south, it's 14.3 SEER2. Most homes benefit from a system rated 15 SEER2 or higher, which balances reasonable upfront cost with meaningful energy savings.

How much does SEER2 save?

Going from a 13 SEER2 to a 16 SEER2 system can cut cooling costs by roughly 20 percent. The exact savings depend on your home's size, climate, and how much you run the AC. We can run a payback analysis to show how long a higher-efficiency unit takes to pay for itself.

More than just the rating

SEER2 is a ceiling, not a guarantee. Proper sizing, quality installation, and sealed ductwork determine whether your system actually performs to its rated efficiency. A poorly installed high-SEER2 system can underperform a well-installed mid-efficiency one.

Want help choosing the right efficiency for your home and budget? We size and install systems to deliver their rated performance — and explain the numbers in plain language.

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