What is the difference between SEER and SEER2?

SEER2 is the updated testing standard as of January 2023. It uses a higher static pressure to simulate real-world conditions more accurately. SEER2 ratings are typically about 4.5% lower than equivalent SEER ratings.

Modern air conditioner with SEER efficiency rating label

Understanding SEER Ratings: What They Mean for Your Energy Bills

A complete guide to SEER ratings and how they impact your home's cooling efficiency and costs.

What is SEER?

SEER stands for Seasonal Energy Efficiency Ratio. It measures how efficiently an air conditioner or heat pump converts electricity into cooling over a typical cooling season.

The formula is simple: SEER = Total cooling output (BTUs) ÷ Total electrical energy input (watt-hours)

Key Points:

Higher SEER = more efficient = lower energy bills
SEER represents average efficiency over an entire cooling season
It accounts for varying outdoor temperatures and humidity levels
Similar to MPG ratings for cars, but for cooling efficiency

SEER Rating Scale

8-12 SEER

Outdated

Common in units manufactured before 2006. These systems are far below current standards and should be replaced for significant energy savings.

13-14 SEER

Basic

Was the minimum standard until 2023. Still functional but considered entry-level efficiency by today's standards.

15-17 SEER

Good

A solid choice for most homeowners. Offers good balance between upfront cost and long-term energy savings.

18-21 SEER

High Efficiency

Premium efficiency range. Best for hot climates with heavy AC usage. Often includes variable-speed technology for optimal comfort.

22+ SEER

Ultra Efficient

Top-of-the-line efficiency. Maximum energy savings and comfort features. Best ROI in regions with long, hot summers.

SEER vs. SEER2: What Changed?

As of January 2023, the Department of Energy introduced SEER2, a new testing standard that better reflects real-world operating conditions.

SEER (Old Standard)

Used lower static pressure (0.1" WC)
Tested in more ideal conditions
Produced higher efficiency numbers

SEER2 (New Standard)

Uses higher static pressure (0.5" WC)
Simulates real ductwork conditions
Ratings are ~4.5% lower than SEER

Conversion: SEER2 ≈ SEER × 0.955. So a 16 SEER unit is approximately 15.28 SEER2.

Minimum SEER Requirements by Region

The federal government sets minimum efficiency standards that vary by region:

Northern Region

(Most states north of the Mason-Dixon line)

14 SEER2

Southern Region

(Southeast and Southwest states)

15 SEER2

Energy Savings Comparison

Here's how different SEER ratings compare in terms of annual energy costs (based on average usage and $0.15/kWh electricity rate):

SEER Rating	Annual Cost*	Savings vs. 10 SEER
10 SEER	$540	—
14 SEER	$386	$154/year (29%)
16 SEER	$338	$202/year (37%)
18 SEER	$300	$240/year (44%)
21 SEER	$257	$283/year (52%)

*Based on 2,000 hours of operation and 3-ton system. Actual costs vary by location and usage.

Choosing the Right SEER for Your Home

Consider Your Climate

Hot climates (Texas, Arizona, Florida) benefit most from high-efficiency units. In mild climates, the payback period for premium efficiency is longer.

Calculate Payback Period

Divide the price difference between units by the annual energy savings to find how many years until the higher-efficiency unit pays for itself.

General Recommendations

Mild climate, budget-conscious: 14-15 SEER
Moderate climate, balanced approach: 16-17 SEER
Hot climate, heavy AC use: 18-21 SEER
Maximum efficiency, long-term stay: 22+ SEER

Frequently Asked Questions

What is a good SEER rating for an air conditioner?

A SEER rating of 15-17 is considered good for most homes. Units with 18+ SEER are high-efficiency, while the minimum standard is 14-15 SEER depending on your region.

Is a higher SEER rating worth the extra cost?

It depends on your climate and usage. In hot climates where AC runs frequently, higher SEER pays back faster. Calculate your expected savings versus the upfront cost difference.

Does SEER affect heating efficiency?

No, SEER only measures cooling efficiency. For heat pumps, look at HSPF (Heating Seasonal Performance Factor) for heating efficiency ratings.

Check Your Current System's Age

Older systems have lower SEER ratings. Find out how old your AC is and consider if an upgrade could save you money.

Use the Age Calculator