Help With GE Furnace Age

Gas fired 150,000 Btuh with Belt-Drive motor so we know its pre-1980

Thoughts on age of unit.

Mdl: 21LG-30J2 / S/N: 24-303-022

The upflow gas fired forced air furnace located in the basement was operated from it thermostat thru a normal cycle. The furnace should be considered as end of life budget for replacement :p:D

House was built in late 50’s … I’m guessing Unit is Original OR close.

Prolly not quite that old Ida guessed mid 60’s

If that furnace was a tree it would be 50 feet tall. Probably last forever too, seein as it lasted this long. New furnace will use less fuel.