Sears used multiple different manufacturers over the years to produce air conditioners and heat pumps that they sold under their Kenmore brand. So there is no single recipe for figuring out age from the serial number.

    But, if you are pretty sure that the unit was manufactured after 1990, which eliminates earlier mutations, it narrows down to either the first two or second two numbers in serial number as the year of manufacture. There may be a single letter before the numbers, which you can ignore. When you come across a serial number where both sets of numbers are a possibly correct, you may have to check the ANSI compliance date to see which one is the winner.

    In the example shown below, it was marked at the bottom of the data plate that the unit (a package heat pump) was manufactured by Goodman, and they go by the first two numbers—so it is 1998. When the data plate references the actual manufacturer you can assume that the serial number complies with their system. Also, if you look carefully around the data plate, the manufacture date is sometimes stated outright, usually in an upper corner.

    For the age of another brand or manufacturer, go to our blog post How do I determine the age of my air conditioner? And to determine the size of your Sears Kenmore unit, go to our blog post What size in tons is a Sears Kenmore air conditioner or heat pump from the model number?

    To determine other key specs of your HVAC system, see one of these other blog posts:

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

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

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

    To find the age of other home components, go to How can I find out the age of a roof? and How do I determine the age of an electrical panel? and How do I determine the age of my water heater? For life expectancies, visit What is the average life expectancy of the components of a house? 

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Field Guide for Home Inspectors, a quick reference for finding the age of 154 brands of HVAC systems, water heaters, and electrical panels, plus 210 code standards for site-built and manufactured homes, and the life expectancy rating of 195 home components. Available at amazon.com for $19.95.
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  To learn more about heating and air conditioning systems, see these other blog posts: 

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

• 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.