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To find out the age of another brand of air conditioner or heat pump, go to How do I determine the age of my air conditioner?, which has a listing of all major manufacturers and links to instructions for decoding their serial numbers.

Whatever year your figure out, it’s a really old system. This home was built in 1979, so we determined it that way.

Because the “8” may be for 1968,1978, or 1988, you want to look at the ANSI certification year, or year of construction of the home, for guidance. So the serial number of the unit below indicates it was manufactured in 1978.

For units from the late 1960s thru the late 1980s, there is a different serial number code, with the single number after an initial letter being the year of manufacture.
