If you’ve looked into buying a new air conditioner lately, you probably noticed that SEER ratings are kind of a big deal. But what exactly is a SEER rating, and how should it factor into your decision when choosing a new A/C unit?

What SEER Means

SEER stands for Seasonal Energy Efficiency Ratio. It measures the maximum possible efficiency for a central air conditioning unit during a cooling season. Put simply, it measures the energy efficiency of an air conditioning system.

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How SEER is calculated

The rating is calculated by dividing the amount of heat removed from the conditioned space during a period of time by the amount of electricity consumed by the unit during that same period of time.

SEER ratings take into account how a unit performs through a range of temperatures by using data from an extended period of time, or a cooling season.

A higher SEER rating means less electricity is used to cool the space.

What SEER Rating Should I Look For?

ac and heating units outside of home

Today’s air conditioners have SEER ratings that range from 13 to 25. Units made in earlier decades have SEER ratings as low as 6.

Legal requirements

The Department of Energy (DOE) established the first SEER rating requirements for central air conditioners in 1992, and the SEER rating required for central air conditioners at that time was 10.

The latest updates to SEER rating requirements, which were implemented in 2015, set up different rating requirements depending on what region of the US you live in.

If you live in the North, the SEER rating requirement is now 13. For the Southeast and Southwest, the SEER requirement is now 14.

Air conditioning contractors are required by law to install products that meet these regional SEER standards.

Why choose a higher SEER rating?

Now that you know what the minimum SEER rating for your region is, you might be wondering why you’d want to buy an A/C unit with a higher SEER rating than the requirement.

The answer is long-term savings. Air conditioning units with higher SEER ratings cost more up-front, but that cost can be offset by the money you save using less electricity to cool your home.

Use this spreadsheet savings calculator from Energy.gov to estimate how much you could save with a higher SEER rating.

Consult an air conditioning professional for expert advice about finding the right SEER rating for you, or do your own research and calculations to determine what SEER ratings can bring you the most savings while fitting your budget.

Additional Indicators of Efficiency


Energy Efficiency Ratio (EER) measures the efficiency of a unit at a set outside temperature, a set inside temperature, and 50 percent relative humidity. This efficiency rating does not measure how the unit performs through a range of outside temperatures, like SEER does.

Like SEER, a higher EER rating means higher energy efficiency. However, EER is typically used to compare small air conditioners that cool single rooms, such as window units.


You’ve probably heard of this symbol of energy efficiency, and chances are the ENERGY STAR label appears on at least one appliance in your house.

The ENERGY STAR program was established in 1992 by the Environmental Protection Agency (EPA). Products that carry the ENERGY STAR label are independently certified to meet the EPA’s standards for performance and savings.

An ENERGY STAR certified central A/C unit has a higher SEER and EER rating and uses less energy than a conventional unit.

This label can help narrow down the overwhelming range of choices, since you already know that a unit carrying the label meets stricter standards and outperforms a conventional model.

The benefits of energy efficiency

electric power station

A major reason to consider a more energy-efficient air conditioner is the energy savings. Lower utility bills means more money to use for other things, such as home improvement projects, family trips, or retirement savings.

Energy efficiency also helps the environment by using less electricity, and who doesn’t want to help their pocketbook and the environment at the same time? Reduced electricity use means that power plants burn a smaller amount of fossil fuels and release less carbon dioxide into the atmosphere.  

Consider these other indicators of energy efficiency when choosing a new air conditioner—it’s a win-win for you and for the environment.

The Bottom Line

SEER ratings are important to understand as you consider updating your central A/C, and educating yourself on other factors can help as well. Remember:

  • There are other indicators of energy efficiency. Look out for the ENERGY STAR label, and pay attention to EER ratings too.
  • Size matters. Get a unit that is correctly sized for your space, or it won’t function at optimum levels.
  • Insulation is important. If your home isn’t keeping in heat or cooled air, the efficiency of your A/C unit is compromised.
  • Performance affects efficiency. Schedule yearly maintenance appointments so you can be sure your HVAC system is working at optimum levels.

Call a Best Pick air conditioning and heating contractor today to get expert advice on SEER ratings, new A/C units, and increasing the energy efficiency of your HVAC system.