HVAC Basics: What’s a Good SEER Rating?

Shopping for a new HVAC system can feel like a daunting task. After all, how does the average person know what makes a good system? One factor that you can look at is the unit’s SEER rating. In this post, we’ll cover the basics of what a SEER rating is, what makes for a good rating, and what to look out for as you shop. Keep reading to learn more.

What is a SEER rating?

Put simply, a SEER rating is a measure of how efficiently your heating and cooling system works. It stands for Seasonal Energy Efficiency Ratio. Though, sometimes, it’s also written out as a Seasonal Energy Efficiency Rating.

However you phrase it, a SEER rating is the ratio of an HVAC unit’s cooling output over an entire cooling season, divided by the amount of energy it uses in Watt-Hours. A system’s cooling output factor is found by using a consistent indoor temperature compared to the energy that it takes to maintain that at a variety of outdoor temperatures. These temperatures range from 60 degrees up to over 100 degrees.

What’s a good SEER Rating?

Generally speaking, the higher the SEER rating, the better the unit’s efficiency. These days, new units must have a rating of at least 13 and most have a rating between 13 and 21, though some models may go even higher. Older and lower-end models, on the other hand, can have a lower rating. For reference, most builder-grade HVAC units have a SEER rating of 8 or 9.

However, keep in mind that the rating is a measure of the HVAC unit’s maximum possible efficiency. It may not always function at that level. For the sake of comparison, SEER ratings function a lot like a car’s gas mileage. Just because a car gets up to 35 miles per gallon on the highway, doesn’t mean it always functions at that level. In city traffic, your MPG is bound to be much lower.

Minimum SEER ratings by region

In an effort to ensure the comfort and safety of citizens, the US Department of Energy (DOE) placed minimum energy efficiency standards on a variety of household appliances, including HVAC systems. Where they’re are concerned, these standards take the form of a minimum SEER rating. However, these ratings aren’t one-size-fits-all. Since weather patterns differ across the country, the DOE varied the minimum rating by region.

They divide the country into three separate regions: Southwest, Southeast, and North. The regions are broken up as follows:

• Southwest: Arizona, California, Nevada, and New Mexico
• Southeast: Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, the District of Columbia, and the U.S. territories
• North: The remainder of the United States

The minimum SEER rating requirements for each region are:

• Southwest: 14
• Southeast: 14
• North: 13

The bottom line

As you shop for a new HVAC unit, you’ll see that there are a range of SEER ratings available. Keep the following factors in mind as you focus in on which unit may ultimately work best in your home:

• Make sure the unit meets the minimum requirements: The minimum SEER rating for your region is the absolute lowest rating that companies are allowed to sell you, even if you ask them for lower. Keep your region’s minimum in mind as you shop. This will help you buy a system well-suited for the climate.
• Remember that your system won’t always work up to its SEER rating: Like miles per gallon in a car, the SEER rating measures the unit’s maximum possible efficiency. However, remember that your system will only be able to reach those standards in near-ideal conditions. Be sure to choose an energy-efficient system that you’re confident will keep you comfortable at all times.

Still have questions? Talk to an expert

Think you need more help finding the right SEER rating? Call an HVAC professional to help you evaluate your home’s needs and to find the right unit for your home.