How old is my Westinghouse HVAC furnace?

Serial number age decoder for Westinghouse HVAC furnaces: 6 format eras, the decode rule in plain English, transcribed tables, and the official lookup.

• Westinghouse HVAC furnace serial numbers in the era not stated format encode the year as digits 7-8 = first two numerals after the dash (97 = 1997) and the month as final letter ('see chart below' - chart NOT present on the fetched page) (source: building-center.org).
• Example: serial 21584-97B decodes to February 1997.
• Westinghouse HVAC furnace serial numbers in the 1970 to 1979 format encode the year as digit 2 = last digit of year, 1970-1979 only (1 = 1971) and the month as letter 1 (chart referenced but NOT present on the fetched page) (source: building-center.org).
• Example: serial A16789 decodes to January 1971.
• Westinghouse HVAC's official lookup at westinghouse.com returns warranty / registration lookup.

Format eras

• 1980 to 1984 PARTIAL
  A#####digit 2 = last digit of year, 1980-1984 only (3 = 1983)
• 1970 to 1979 PARTIAL
  A#####digit 2 = last digit of year, 1970-1979 only (1 = 1971)
• era not stated PARTIAL
  #####-##Adigits 7-8 = first two numerals after the dash (97 = 1997)
• era not stated VERIFIED
  AAA#########digits 4-5 of the serial, i.e. the first two numerals after the 3-letter prefix (03 = 2003
• era not stated VERIFIED
  AA#A### A#### ####digits 3-4 after the middle factory letter (91 = 1991)
• era not stated VERIFIED
  A#A####-#####digits 4-5 (99 = 1999)

How to read the serial

1980 to 1984 formatPARTIAL

Shape A##### · example M38778 · confidence medium

Year

digit 2 = last digit of year, 1980-1984 only (3 = 1983)

Week or month

month = letter 1 (chart referenced but NOT present on the fetched page)

1970 to 1979 formatPARTIAL

Shape A##### · example A16789 · confidence medium

Year

digit 2 = last digit of year, 1970-1979 only (1 = 1971)

Week or month

month = letter 1 (chart referenced but NOT present on the fetched page)

Example: serial A16789 decodes to January 1971.

era not stated formatPARTIAL

Shape #####-##A · example 21584-97B · confidence medium

Year

digits 7-8 = first two numerals after the dash (97 = 1997)

Week or month

month = final letter ('see chart below' - chart NOT present on the fetched page)

Example: serial 21584-97B decodes to February 1997.

era not stated formatVERIFIED

Shape AAA######### · example GBB030708229 · confidence high

Year

digits 4-5 of the serial, i.e. the first two numerals after the 3-letter prefix (03 = 2003)

Week or month

month = digits 6-7 (07 = July)

Plant

none; the 3-letter prefix is a model-series code ("can be any combination of letter and number sequence, typically like model number"), not a plant

Example: serial GBB030708229 decodes to July 2003.

Listed under Nordyne in the source; Westinghouse HVAC is named in that format's family and the corporate link is an estimate, not a checked fact.

era not stated formatVERIFIED

Shape AA#A### A#### #### · example MN3D102 F3891 4228 · confidence medium

Year

digits 3-4 after the middle factory letter (91 = 1991)

Week or month

week = digits 1-2 after the middle factory letter (38)

Plant

middle letter = factory code (F in the example; Rheem uses F, M, G, W, N)

Example: serial MN3D102 F3891 4228 decodes to week 38 of 1991.

Listed under Nordyne in the source; Westinghouse HVAC is named in that format's family and the corporate link is an estimate, not a checked fact.

era not stated formatVERIFIED

Shape A#A####-##### · example G6R9905-05028 · confidence high

Year

digits 4-5 (99 = 1999)

Week or month

month = digits 6-7 (05 = May)

Plant

letters 1 and 3 + digit 2 = unexplained prefix (no table)

Example: serial G6R9905-05028 decodes to May 1999.

Listed under Nordyne in the source; Westinghouse HVAC is named in that format's family and the corporate link is an estimate, not a checked fact.

Where the data plate is on a furnace

Inside the furnace: remove the upper (burner) access door and look on the inside of the door, on the blower compartment wall, or on a sticker facing you at the burner deck.

General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.

For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Furnace at 15 to 25 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.

What we could not confirm

• The era not stated format is only partially confirmed (PARTIAL).
• The 1980 to 1984 format is only partially confirmed (PARTIAL).
• The 1980 to 1984 format is documented but not decodable here: example M38778 does not decode with the derived engine.
• The 1970 to 1979 format is only partially confirmed (PARTIAL).
• Westinghouse HVAC is treated as sharing Nordyne's format because the source lists it in that family; the corporate relationship itself is an estimate.
• Most styles of any Nortek brand: root style 1, Rheem-style F3891 4228, G#R YYMM-#####, plus three Westinghouse-specific legacy styles added as rules (21584-97B; M38778 1980-84; A16789 1970-79) - all three have their month-letter chart missing from the source (PARTIAL). westinghousehvac.com redirects to westinghouse.com/pages/air-comfort (200), a brand page not a lookup.

Sources

• https://www.building-center.org/westinghouse-hvac-age/
• https://www.building-center.org/frigidaire-hvac-age/
• https://www.building-center.org/philco-hvac-age/
• https://www.building-center.org/nordyne-hvac-age/
• img: Nordyne-style-1-2023.jpg (transcribed)
• https://www.building-center.org/intertherm-hvac-age/
• https://www.building-center.org/gibson-hvac-age/
• https://www.building-center.org/broan-hvac-age/
• img: Nordyne-style-2-2023.jpg (transcribed)
• https://www.building-center.org/tappan-hvac-age/
• https://www.building-center.org/miller-hvac-age/
• https://www.building-center.org/kelvinator-hvac-age/
• https://www.building-center.org/maytag-hvac-age/
• https://westinghouse.com/pages/air-comfortofficial

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