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What Is SEER? (2024 Guide)

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Author Image Written by Brenda Woods Updated 06/24/2024

SEER, or Seasonal Energy Efficiency Ratio, is a rating scale that measures an HVAC system’s energy efficiency. According to Energy.gov, a SEER rating is a system’s cooling output divided by the energy it uses during the warmer part of the year. A higher SEER rating equals a more energy-efficient system. 

The SEER rating helps homeowners compare energy efficiency when choosing an air conditioning system. This guide explains what SEER is, how it relates to your HVAC system, and the benefits of a high SEER rating.

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These are some of the primary benefits of a high SEER rating:

Lower Energy Bills

A high SEER rating means your air conditioning unit consumes less energy during the cooling season, increasing your energy bill savings. A more efficient system can cool a space more quickly, lessening the amount of time it runs. According to the U.S. Department of Energy, you could save 20%–40% of your cooling energy costs by replacing an older system with a high SEER-rated air conditioner. 

Reduced Carbon Footprint

Power plants that generate electricity typically rely on fossil fuels, such as coal or natural gas, to produce energy. This leads to greenhouse gas emissions. High-efficiency power plants create fewer greenhouse gasses and put less strain on your local power grid. Newer, more efficient plant models also have safer, ozone-friendly refrigerants.

Incentives and Rebates

Rebates at the state and national levels may be available for new HVAC models with high SEER ratings. These incentives can make energy-efficient AC units more affordable. 

Energy Star-certified air conditioning units are eligible for a $600 tax credit from January 1, 2023 to December 31, 2032. Split systems must have a SEER rating of at least 16. Check the Energy Star Rebate Finder to discover local rebates and other special offers. 

More Efficient Moisture Removal

High-efficiency systems are better at removing moisture. The cycling frequency of AC equipment affects its ability to remove water from the air. Longer cycles can remove moisture more efficiently. Older systems cool too quickly without removing moisture, which can cause mold and problems with indoor air quality. A high SEER rating may be particularly important for people with allergies or respiratory conditions.


In 2023, SEER was replaced by SEER2 to better represent the external field conditions of installed HVAC units in different U.S. regions. SEER2 considers regional climate data and other factors, such as humidity and temperature changes, to measure energy efficiency more accurately.

SEER2 applies to all new residential split-system ACs, single-package ACs, and split-system and packaged heat pumps in the U.S. The new standards require a minimum SEER rating of 14 for systems in the northern U.S. and 15 SEER, or 14.3 SEER2, in the South.


EER, which stands for Energy Efficiency Ratio, is another measure of air conditioner efficiency. EER measures the instantaneous efficiency at a specific level rather than over an entire cooling season and is typically used for smaller units. Similar to SEER, the higher the EER, the more energy-efficient the system. Here are the key differences between the two measures.

  • Used for central air conditioning and heat pumps
  • Determines expected energy efficiency for the entire season
  • Accounts for the system starting and stopping
  • Used for window AC units
  • Determines energy efficiency at a single air temperature—95 degrees Fahrenheit
  • Accounts for the system running at a steady state

How SEER Is Calculated

A SEER rating is calculated by dividing the total number of BTUs (British thermal units) by the total amount of energy expended by the air conditioner in watt-hours. This calculation provides an average efficiency rating over the course of the cooling season rather than just a single moment in time.

A testing procedure known as the AHRI (Air Conditioning, Heating, and Refrigeration Institute) Standard 210/240-2023 is used to calculate SEER ratings. It involves subjecting the air conditioner to a series of controlled conditions that simulate different outdoor temperatures and indoor humidity levels. The unit’s performance is measured and recorded at each condition.

SEER ratings are standardized to ensure accuracy and consistency across different air conditioner manufacturers and models. The test also considers factors such as unit size and design, refrigerant type, and environmental temperature and humidity levels.

After testing, the SEER rating is calculated using a weighted average of the unit’s performance during each testing condition. Most new AC units have a yellow sticker labeled “EnergyGuide” that contains the SEER rating. You can also find it at the top of the manufacturer label by the model and serial number.

If you’re thinking of upgrading your system, below is a SEER rating chart and the average cost of a new HVAC system. Keep in mind that prices vary significantly depending on the AC unit type, size, brand and model, SEER rating, and BTUs.

SEER RatingSizeAir Conditioning (BTUs)Average Price*
143.5 ton42,000$4,000
155 ton57,000$4,225
163 ton33,000$2,700
175 ton54,000$4,700
184 ton48,000$6,400

*Average costs of whole-home AC units from The Home Depot.

Our Conclusion

The top air conditioners on the market have high SEER ratings and are more efficient, helping to lower energy bills and lessen environmental strain. Homeowners who buy AC units with high SEER ratings may qualify for energy efficiency rebates or tax credits.

While getting a rough cost estimate for a new AC yourself is possible, it’s best to request quotes from several professionals and compare. A professional HVAC contractor can help you determine the best unit type and size for your home and provide a more accurate estimate that includes labor and other variables.

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FAQ About SEER (Seasonal Energy Efficiency Ratio)

What is the minimum SEER rating for a federal tax credit?

The minimum SEER rating for a $600 federal tax credit is 16 on Energy Star-certified equipment. According to the U.S. Environmental Protection Agency, this credit is effective for products purchased and installed between January 1, 2023, and December 31, 2032.

Why are energy rates always changing?

Energy rates change due to variations in electricity demand, fuel costs, and the availability of generation sources and power plants. Prices are usually highest in summer when the demand for power is higher.

Why is SEER rating important?

A SEER rating is important because it tells you how efficiently your air conditioning unit cools your home. The higher the SEER rating, the less energy used and the lower your energy bill.

Is it worth going from 13 SEER to 16 SEER?

Going from 13 SEER to 16 SEER increases your AC unit’s efficiency, which could translate to a lower utility bill. 

Is SEER 21 worth the money?

A SEER 21 air conditioner is expensive, but it may be worth the money if you live in an area where it’s hot year-round.

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