Age of Lennox furnace

Need age on a old Lennox Natural Gas furnace. S/n G9-110 M-1 67-4

Nothing I have goes back far enough for this one.

Lynn W. Gerving

I have some inconsistent data on Lennox that would seem to indicate July 1969.

Thanks Russel. That about what is was guessing but wasn’t sure.

Lynn W. Gerving

Hi to all,

Lynn, you and Russel are in the right area, Prestons list it as current for 1967 & 1968. 1100,000 btu input with 57% efficiency.

It is well past its intended life span and very inefficient.



I have some information that indicates that the “67” in the serial number is when the model first hit the market.

However, I have some conflicting information that indicates that the “67” is the ANSI date.

My research and notes continue…