How old is my Concord unit?

Concord is part of Lennox International (Allied Air Enterprises). 2 serial formats sourced across central air conditioner, heat pump, furnace.

• Concord air conditioner serial numbers in the 1973 to present format encode the year as digits 3-4 (YY) and the month as letter at position 5 (A=Jan .. M=Dec, I skipped) (source: building-center.org).
• Example: serial 5899L17212 decodes to November 1999.
• Concord air conditioner serial numbers in the before 1972 format encode the year as digits 1-2 and the month as digit(s) 3(-4), 1-12 (source: building-center.org).
• Example: serial 6512 decodes to December 1965.
• Concord's official lookup at concord-air.com returns warranty / registration lookup.

Decoder pages by product

Format eras

• 1973 to present VERIFIED
  ####A#####Central Air Conditioner, Heat Pump, Furnace, Packaged Unit
• before 1972 VERIFIED
  ####Furnace, Central Air Conditioner

What we could not confirm

• Concord is treated as sharing Lennox's format because the source lists it in that family; the corporate relationship itself is an estimate.
• Allied Air brand (site footer). Styles 0183290431 (old style, YY WW last four) and 4601J19567 (new style, plant 46 Blackville). Concord chart supplies the plant table (46/84/16/60/56) and a week-to-month table. Allied serial lookup: https://apps.alliedconnect.com/WarrantyPeriodLookup/ExtendedWarrantyLookup.aspx?Alias=ALD&USERSORG=AR01

Sources

• https://www.building-center.org/lennox/
• https://www.lennox.com/residential/owners/assistance/warranty/official
• https://www.building-center.org/concord-hvac-age/
• https://www.concord-air.com/warranty-and-support/official

Concord central air conditioner Concord heat pump Concord furnace Lennox International and Allied Air family Guides