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How can I find out the SEER of my air conditioner?

Saturday, July 28, 2018

There are seven different ways you can determine either the exact or approximate SEER of your heat pump or air conditioning system. Let’s start with the easy, simple ways to get an exact number, and work down to other methods that will provide an approximate rating for your system:

1) If the yellow and black rating sticker is still intact on the side of the condenser and legible, like in the photo below, it will tell you.

2) Look for a sheet taped to the front of the air handler (indoor unit), where the HVAC contractor has listed the performance data for the system.

3) Some manufacturers encode the SEER rating in the beginning of the model number on the data plate of the condenser. For example, the “XC21” at the beginning of the model number of the Lennox condenser shown below indicates it is rated at 21 SEER. Older systems do not do this.

4) If it is a replacement system and you have a copy of the building permit, it will usually also show the SEER of the system. In many areas, building permits can be looked up online at the county or city building department’s website, and it will often show the SEER of the system in the description of the work or the attached notes. The SEER of a heat pump or a/c system is the result of the combination of the performance of both the condenser and air handler, so the actual SEER listed on the contractor’s performance data sheet or the building permit may be slightly higher or lower than the SEER rating of the condenser alone.

5) If you look for the manufacturer’s logo plate on the side or top of the condenser, it will may have a model name like “Comfortmaster 1200” or “RoyalAir 10,” which indicates the approximate—but not always exact—SEER of 12 or 10 for the system. 

6) If you know the year of manufacture of the system, which is usually coded in the data plate of the condenser unit as the first two or second two numbers of the serial number, you can determine an approximate SEER based on the when it was made. See our blog post “What is the SEER of my old air conditioner?” for more on this approach. 

7) And last, if all else fails and you really, really want to know the exact SEER of the system, jot down the model number and serial number from the data plate and call or email the manufacturer’s customer service department with the information and a request for the SEER rating of your unit.

    There is one potential flaw in several of these techniques. It has been required since 2006 that both the condenser and air handler be replaced unless it can be verified that the new half of the system that the HVAC contractor is switching out is matched by the manufacturer for performance with the remaining component. However, if part of the system was replaced by someone willing to do it without the required building permit, the SEER rating efficiency of the new part of the system may not be achieved because of the mismatch to the older part. If, for example, your outdoor unit is LENNOX and the indoor unit is GOODMAN, you definitely have a mismatched system and there is no way to determine the actual efficiency rating.  

    To learn more about the requirement to match condenser and air handler, click on the link below to download a pdf info sheet from the Florida Department of Community Affairs.


    Also, see our blog posts 
What is the difference between SEER and SEER2? and How can I find out the size of my air conditioner? and How can I find out the age of my air conditioner or furnace?

• • • • • • • • • • • • • • • • • • • • • • • • • • • • 

  To learn more about heating and air conditioning systems, see these other blog posts:

How can I find out the SEER of my air conditioner? 

My air conditioner won't turn on. What's wrong? 

How can I find out the size of my air conditioner? 

How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump? 

Where is the air filter for my central air conditioner and furnace? I can’t find it? 

Does an old air conditioner use more electricity as it ages? 

How did homes stay cool in Florida before air conditioning? 

What is wrong with an air conditioner when the air flow out of the vents is low?

Why has the thermostat screen gone blank? 

Why does it take so long to cool a house when an air conditioner has been off for a while? 

Why is my air conditioner not cooling enough? 

What are the most common problems with wall/window air conditioners?  

Will closing doors reduce my heating and cooling costs? 

   Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles. 

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