The first digit of the serial number is the last digit of the year for Mitsubishi. So “6” could be “2006” or “2016,” and you would need to look at the condition of the unit, and/or the date of the ANSI code at the upper part of the data plate, to determine which one. Here’s a recent example from an air handler manufactured in 2007.

And the data plate from the condenser unit for the same system, which was manufactured in 2008.

    And this is another example of a system manufactured in 2020. Although it also has a single letter in the serial, you use the same first digit system for age. We knew that was 2020, and not 2010, because it was at a new house. But the ANSI Code date was 1995—so that was not much help in sorting it out.

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

• How can I find out the age of my air conditioner or furnace? 

• 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.