furnace age please

I need the age of the furnace Concord 80 Plus Gas Furnace Model #GCJ125020-4A Serial #8400D19948



Concord is made in Ohio. It is part of Armstrong furnace which is owned by Lennox.

It was manufactured in April of 2000.

Thanks David

Hello my name is Virgil Heath. I’m new to home inspections I was woundering how David came up with the age of the furnice? What numbers did you go buy? Any help would be GREAT.

I see a lot of questions in this forum related to furnace ages. The best book I ever purchased (7" x 7") is a book published by CarsonDunlap called the Technical Reference Guide. I paid $59.00 for the book at an inspection conference. Just turn to the manufacturers page in the book and you can immediately identify the furnace age. I don’t know for sure, but it seems like the book covers every brand of furnace ever made. A must reference book for your tool bag.

Virgil - the second set of numbers in the serial number in the question posted by Steve is how you know it was manufactured in 2000.