Lennox A/C - I need the age , please.

[Michael H. Butters]

Could somebody please tell me what the age of this unit is?
Lennox M# HS26-048-3P Serial # 5899A - 33086

Thanks in advance guys.

[Jae Williams]

LENNOX: Newer units – (Serial Number) First two numbers equal manufacturing plant #, 2nd two are year and letter in fifth slot is month (A thru M minus I). So 5898G 07568 would be Plant # 58, Year of MFR would be 98 and month would be July.
Prior to 1974, the first two digits will be year, and the third-fourth digits are the month

So...1999

[Michael H. Butters]

Thank you Jae. I really appreciate it.