A SEER rating measures an air conditioner’s efficiency. The acronym stands for Seasonal Energy Efficiency Ratio and is calculated by dividing the total amount of cooling provided over a typical cooling season by the total electrical input. Units with higher SEER ratings are more efficient and produce lower energy bills.
The SEER rating is the maximum rating, which is achieved when a central air conditioning unit is operating at peak efficiency. Just as a car will get fewer miles per gallon of gas during city driving than highway driving, an air conditioner’s SEER rating may be less under certain conditions.
Central air conditioning units range from 13 to 25 SEER. 13 SEER is the least efficient rating, and 25 is the most efficient. You can find a unit’s SEER rating on the yellow and black EnergyGuide sticker or in the unit’s specifications.
The SEER rating is one factor to consider when you’re in the market for a new air conditioner. However, a higher SEER rating is not necessarily a better choice. Many other elements should be considered with the SEER rating to get the best bang for your buck.
Which SEER Rating Is Best?
No particular SEER rating is best. The SEER rating represents the potential efficiency of the unit under perfect conditions. 25 SEER is the highest rating, but which is best for you depends on the size of the home, ductwork, insulation, ventilation, and a wide range of other variables.
Before the nineties, there were no national minimum SEER requirements. In 1992, all new units became required to have a minimum SEER rating of 10. That minimum was raised to 13 SEER in 2006. 13 SEER is still a decent rating for a unit, especially if it replaces an old 8 SEER unit. ENERGY STAR qualified central air conditioners must have a SEER rating of 15. 16 SEER is a good efficiency rating for a new air conditioner, and anything above 16 SEER is excellent. Don’t rush out to buy an air conditioner with the highest SEER rating you can find, though. A great efficiency rating doesn’t mean it’s a great investment.
In general, units with higher SEER ratings keep houses cooler than units with lower ratings, but this has to do with the units’ components rather than their ratings. Units with higher SEER ratings often have two-stage or variable-speed compressors and variable-speed blowers, meaning they have high and low settings. Dual-stage systems are better at removing humidity and cooling evenly than single-stage systems because they run for extended periods. Units with lower SEER ratings usually have single-stage compressors and single-speed blowers that only turn on and off. Single-stage systems have difficulty removing humidity because they shut off frequently and don’t run for an adequate time. The absence of high and low settings in single-stage systems also causes hot and cold spots in the home.
Units with higher SEER ratings have two other advantages. One, high-efficiency units are generally more eco-friendly, using up to ⅓ less fuel. Two, high-efficiency units are usually quieter, which is a perk if the unit is located near a bedroom window or if an HOA or municipal code has noise restrictions.
Minimum SEER Ratings
In 2015, the U.S. Department of Energy (DOE) modified the minimum SEER requirements, requiring that they differ by geographical region. The minimum rating for northern states continues to be 13 SEER, while the minimum rating for southern and southwestern states has been increased to 14 SEER. In 2023, HVAC efficiency standards will increase the minimum SEER rating to 14 for the northern states and 15 for the southern and southwestern states.
Northern Region: Alaska, Colorado, Connecticut, Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah, Vermont, Washington, West Virginia Wisconsin, and Wyoming.
Southwest Region: Arizona, California, Nevada, and New Mexico.
Southeast Region: 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.
SEER Rating and Cost Savings
Units with higher SEER ratings consume less energy, saving you money on your energy bill. For example, upgrading an outdated 9 SEER air conditioner with a 1.5-ton 15 SEER unit will reduce energy costs by more than 40%, resulting in a cost savings of over $1,000 in 10 years. Replacing an older 10 SEER unit with a new 18 SEER, 3-ton air conditioning system will cut energy costs by nearly 44%, saving about $250 per month or more than $3,000 in 15 years. Despite the savings, a high-efficiency unit may not be worth the purchase price.
Units with higher SEER ratings are more expensive to purchase than units with lower ratings. 16 SEER units may cost $900 to $1,500 more than 14 SEER units, and 21 SEER units may cost $3,000 to $5,000 more. However, you may be able to take advantage of tax credits and government incentives, and manufacturer rebates to lower the cost.
In addition, repair costs for dual-stage systems are often more than for single-stage systems. If the warranty has expired, repairs on a 14 SEER compressor starts around $1,300, and repairs on a 21 SEER compressor begins around $2,000.
SEER Rating vs Ton
There is no relationship between tonnage and SEER. Tonnage refers to cooling capacity, and SEER is an efficiency rating. A high SEER rating will not compensate for an undersized air conditioner. In fact, high-efficiency units often lose cooling power on very hot days due to small compressors, so tonnage matters.
Tonnage does not refer to the weight or mass of the ac unit. Instead, it represents how much heat the unit can remove from an area in one hour. One “ton” can remove 12,000 British Thermal Units, or BTUs, each hour. Your unit’s tonnage should correlate to the square footage of your home. A unit that is too small will be unable to cool the space, while a unit that is too large will waste money and turn on and off more frequently, which could cause the parts to wear out more quickly. Generally, one ton of cooling capacity is needed for every 400 to 1000 square feet of house. Other factors such as ceiling height, number and quality of windows, and room layout should also be considered when sizing an air conditioner. An HVAC professional can help you determine how big of an air conditioner you require.
What SEER Rating Should I Buy?
What SEER rating should I buy? When cost-efficient air conditioning of your home is what you want, finding the right balance between equipment and energy costs is the key. Higher SEER units are more expensive to purchase and repair, and the energy savings may not be enough to offset the costs.
Those living in hot climates will get a better investment return than those in mild climates. Still, a homeowner living in one of the southern-most states is unlikely to get enough years out of an expensive 23 SEER unit to see a return on their investment.
Another thing to consider is how long you will live in the home. If you will be moving soon, it is unlikely that lower energy bills will give you a return on your investment. On the other hand, a high-efficiency AC unit could be a selling point.
As of 2015, the minimum SEER rating is 13 for the north and 14 for the south and southwest. Those standards will increase to 14 and 15 in 2023. 14 SEER is adequate for most houses, but 17 or 18 SEER is a great rating if the unit has a two-speed or variable-speed compressor, even for hot climates. Not only do variable-speed compressors do a better job at cooling, but they are also quieter. In addition, high-efficiency units are better for the environment.
Air conditioner efficiency has come a long way in the last forty years. In 1992, the minimum SEER rating was 10. Before then, there was no national minimum. Today, anything over 13 SEER is considered efficient and will save you money compared to an outdated unit.
Although the SEER rating is important, there are many other factors to consider such as the climate, how long you will reside in the home, purchase price and repair costs. You can save money on your energy bill with a high-efficiency unit, but the cost of a 23 SEER unit will probably outweigh the savings. Remember, a high SEER rating does not compensate for low tonnage.