Heil furnace age help please

I hate to ask, but have a Heil-Quaker furnace I can’t decode. Help is greatly appreciated.

Model: NHGE125AK01
SN: 8020778703

ANSI date on label: 1985
House age: 1965

What’s the system HEIL uses in their serial numbers???

The Carrier Blue Book says it is a 1987.

Preston’s Guide lists it as 1987 also.

1987 is close. That’s probably the date that the model number was available to the public.

Heil has several types of serial numbers because some of their appliances were made in America.

That specific type of serial number for Heil uses the first three numbers as the dating code, i.e., the 8 stands for 1988, and the 02 is the second week, so January 1988.

I don’t know the time frame for Heil, so one could also think that it is 1978, 1988, or 1998, so one does need the ANSI date to make a good determination. In this case the 1985 ANSI date confirms the 1988 build date.

Thanks to all. Much appreciated.