What Are SEER & EER Ratings? An Energy Efficient AC Guide

What Are EER & SEER Ratings?

If you skim through any AC listing, you’ll notice something called a SEER rating or EER rating. Sometimes, you’ll notice both. These numbers can play a big role in the AC shopping process.

Image of energy efficient AC

But what are SEER ratings, exactly? What do they mean? What is an EER rating and how is it different? Both of these ratings are crucial to choosing an AC, but there are some key differences between them that are important to know before you purchase a new unit. We’ll talk about what these ratings mean and how to determine which air conditioning efficiency rating is right for your home.

About Air Conditioning Efficiency

If you take a look at any AC listing, you will notice the unit has an EER rating and, if it’s a mini-split or whole-home system, a SEER rating. These numbers, typically ranging from 8 to 30, indicate how energy efficient the unit is.

Energy efficiency is determined by the unit’s cooling output (measured in BTUs, a topic we covered previously) divided by how much energy the unit consumes (in watts) during one hour of cooling. The higher the number, the more energy efficient that unit is.

Higher efficiency units are typically more expensive to purchase compared to their lower efficiency counterparts, but the investment is worth it in the long run.

An energy efficient unit can save you thousands each year in energy bills, and efficient units are better for the environment as well. In fact, the U.S. Department of Energy (DOE) recently raised the minimum SEER/EER ratings for all cooling units manufactured on or after January 1, 2015, to ensure better environmental protection and lower national expenditures without sacrificing home comfort during the hot summer months. All AC units available at Total Home Supply meet these new requirements.Image of estimated yearly operating cost of energy efficient models


What is an AC EER rating?

EER stands for Energy Efficiency Ratio and is an objective measurement of how efficiently a unit is engineered to run. Determined by a set outdoor temperature of 95° F, a set indoor temperature of 80°, and a relative humidity level of 50%, the air conditioner EER rating indicates how efficiently that unit will run under these specific temperature conditions. Actual temperatures and humidity levels will vary of course, but because EER ratings are all based on the same set of conditions, it becomes a useful tool for comparing units in terms of overall efficiency. Units with an EER rating of 11 or higher are considered efficient.

What is an AC SEER rating?

SEER stands for Seasonal Energy Efficiency Ratio and is a measurement of how efficiently a unit will operate over the course of one cooling season. Unlike EER ratings, SEER ratings are determined by varying indoor/outdoor temperatures as well as varying humidity levels, and the rating takes into consideration temperatures ranging from 60-100° F. SEER ratings are also only used for mini-split HVACs and central air systems, which are larger and use more energy than smaller units such as window or through-the-wall ACs.

Mini split SEER ratings are highly useful in helping homeowners predict their overall energy expenditures for the season, but choosing a unit based on SEER ratings requires a bit more knowledge than the number alone. SEER ratings do not take into consideration average regional temperatures over a cooling season. This means a unit that is energy efficient in Seattle is not necessarily going to be efficient in Santa Fe where average temperatures are much higher, especially in the summer.

Which air conditioner SEER rating do I need?

The U.S. Department of Energy’s new rule in AC energy efficiency is a helpful place to start because it breaks the country down into three regions — North, South, and Southwest — with different energy requirements for each:

  • Air conditioning units in the Northern region of the United States are required to have a SEER rating of no less than 13
  • In the South, the minimum SEER rating is 14
  • In the Southwest, the minimum is 14 SEER with an additional requirement of 11.0-12.2 EER

Keep in mind that AC SEER ratings are only used for mini-split HVACs and central air systems. For window or through-the-wall units, you’ll want to pay attention to EER ratings.

Which air conditioner EER rating do I need?

If you are looking to purchase a window or through-the-wall AC, you will need to look for a unit with an EER rating of at least 10.8 (Northern region) or 12.2 (Southern and Southwest regions).

All mini-splits and whole-home solutions have EER ratings as well, so look for that number in addition to that unit’s SEER rating to ensure the AC you choose is appropriately efficient all-around.

Examples of energy efficient AC units

Now that you know the difference between SEER and EER ratings, you’re probably wondering which energy efficient air conditioner solution is right for you.

Total Home Supply carries a wide selection of energy efficient AC units with both high SEER and EER air conditioner energy ratings. Here are just a few options:

  • The LG LA090HYV1 Art Cool Single-Zone Mini Split AC has a SEER rating of 27.5 and an EER rating of 15.65, making it our most efficient option yet and perfect for residents of South and Southwest states.
  • If you’re looking for an energy efficient window AC unit, the Friedrich CP12G10B 12,000 BTU Window Air Conditioner is a great choice. This Energy Star qualified unit has an EER of 12.1, making it ideal for those who reside in Northern states.
  • For those who are seeking a quiet option, the LG LP073CDUC PTAC Air Conditioner has a 13.3 EER rating for high-efficiency cooling. With quiet operation and dual functionality as a heater, this PTAC unit is great for hotel rooms or assisted living spaces.

We hope that this clears up some confusion surrounding air conditioner energy ratings. If you have any additional questions regarding SEER/EER ratings or energy efficient cooling units, please do not hesitate to contact us at 877-847-0050 and speak to one of our qualified AC specialists.

In the market for a new mini split AC unit? Check out our Multi-Zone Mini Splits Buying Guide to learn everything you need to know before purchasing a new AC system.