What Is SEER and SEER2? Everything You Need to Know About HVAC Efficiency

You’re thinking of upgrading your home’s HVAC, but as you’re researching whether to install AC or a radiant heating system, you can’t seem to make sense of this number that keeps popping up. What is SEER, and what does it have to do with your HVAC? SEER (Seasonal Energy Efficiency Ratio) and the updated SEER2 are efficiency rating systems for HVAC units, and you’ll need to understand how SEER works to find the right cooling system for your home.

What Is SEER for HVAC?

SEER stands for Seasonal Energy Efficiency Ratio and is a type of efficiency rating for HVAC systems. This ratio compares the average amount of cooling an AC unit or heat pump provides during peak cooling season compared to total energy consumption. Units that use less energy to provide ample cooling will receive a higher SEER rating. Higher SEER and SEER2 ratings also equate to a lower monthly energy bill. 

Calculating SEER

To calculate SEER, HVAC professionals divide a unit’s cooling capacity by total energy consumption. 

They will first determine the model’s cooling output in British thermal units (BTUs) for a cooling season, considered about 1,000 hours, then determine the amount of energy, measured in watts, for a season. To find SEER, divide the BTUs of an HVAC system by the watts used in one season.

What Is SEER2?

You may have noticed SEER2 ratings on a few labels while shopping for a new cooling system. SEER2 refers to Seasonal Energy Efficiency Ratio 2, an updated version of SEER that went into effect as the new standard for cooling units as of 2023.

SEER2 is designed to better reflect the real conditions that an HVAC system could be operating under during the testing process, compared to the results from lab testing used for SEER, which were not as close to real-world conditions.

SEER vs. SEER2

SEER2 ratings are actually slightly lower than SEER ratings by about 4.7%. If you’re looking at different types of AC units or heat pumps manufactured after 2023, you’ll see a SEER2 rating. Units made prior to 2023 will have the older SEER rating.

To find a unit with similar efficiency to an existing unit made before 2023, look for SEER2 units that are about 0.5 points lower than your existing unit’s SEER rating. As for the differences in testing, the SEER2 test includes higher total external static pressure during the tests to better account for how ductwork can impact external static pressure in a home in a way that wasn’t happening in lab tests. 

Don’t worry. You don’t need to know the exact science behind it. Just know that the test is new and improved for real conditions so that the unit's rated efficiency has a better chance of matching the actual efficiency it operates with after it’s installed in your home. 

Understanding SEER Ratings

The higher the SEER (or SEER2) rating, the better the efficiency of your new HVAC unit. With the SEER2 updates made in 2023, the minimum SEER for northern states is 14. Because of the higher average temperatures, the minimum SEER for southern states is 15, according to strict guidelines set by the U.S. Energy Information Administration.

For the highest efficiency, look for units with a 21 or higher SEER rating. You should also consult a local HVAC company to help determine which system and SEER rating is best for your needs.

Locating the SEER Rating

Finding the SEER rating for your type of HVAC system is as easy as reviewing the unit’s manual or checking the EnergyGuide label on your unit. However, if you can’t access or locate the EnergyGuide label or the manual has grown legs and walked away in the past five to 10 years (like so many things in our home do), you can also search the model number online or contact the manufacturer to determine the SEER Rating.

Pros and Cons of High SEER Ratings

Having an HVAC system with a higher efficiency rating may seem like the best thing to do, and it does come with several benefits, including lower energy bills each month. However, if you’re looking to lower the up-front cost of installing AC, there are some factors to keep in mind when deciding on the right SEER for your unit. 

Pros

Whether you want to do your part for the environment or simply want to cut cooling costs, opting for a high SEER rating for your HVAC system comes with many benefits.

• Lower electric bills: One of the greatest benefits of upgrading to a high SEER system is that the improved efficiency means your HVAC system will use less energy to operate, reducing your utility bills month after month.

• Smaller environmental impact: According to the Department of Energy, AC uses about 6% of all electricity in the U.S. and contributes 117 million metric tons of CO2 emissions per year. But higher efficiency units use less energy and emit fewer greenhouse gasses.

• Improved indoor comfort: Because of the increased efficiency, a system with a higher SEER will be better at cooling rooms throughout the home (while costing less to do so).

Cons

There are several benefits to choosing an HVAC system with a higher SEER, but keep in mind there are some drawbacks to opting for a higher-efficiency system.

• Higher up-front costs: Although HVAC systems with higher SEER ratings can save you money in the long run, you may pay more up front for highly efficient systems. Fortunately, high-SEER units may qualify you for energy tax credits to bring down the costs.

• Higher repair costs: Repairs for units with a higher SEER may cost 10% to 20% more compared to repairs for units with lower SEER.

• HVAC and duct upgrades: To accommodate a higher SEER, you may need to update the ductwork in your home, which can add to the cost of installing a new HVAC system.