How old is my WaterFurnace heat pump?

Serial number age decoder for WaterFurnace heat pumps: 3 format eras, the decode rule in plain English, transcribed tables, and the official lookup.

• WaterFurnace heat pump serial numbers in the 2012 to present format encode the year as digits 1-2 (YY) -> 2018 and the month as digits 4-5 -> Oct (source: building-center.org).
• Example: serial 180100228 decodes to October 2018.
• WaterFurnace heat pump serial numbers in the 1985 to 2012 format encode the year as letter 1 (table below) and the month as letter 2 (A=Jan..M=Dec, I skipped) -> Sep (source: building-center.org).
• Example: serial UJ1087 decodes to September 2004.
• WaterFurnace heat pump serial numbers in the before 1984 format encode the year as digits 2-3 (YY) -> 1983 and the month as letter 1 (A=Jan..M=Dec, I skipped) -> Apr (source: building-center.org).
• Example: serial D8367019 decodes to April 1983.
• WaterFurnace's official lookup at warranty.waterfurnace.com returns warranty / registration lookup.

Format eras

• 2012 to present VERIFIED
  #########digits 1-2 (YY) -> 2018
• 1985 to 2012 VERIFIED
  AA####letter 1: A=1985/2010 B=1986/2011 C=1987/2012 D=1988/2013 E=1989/2014 F=1990/2015 G=1991 H
• before 1984 VERIFIED
  A#######digits 2-3 (YY) -> 1983

How to read the serial

2012 to present formatVERIFIED

Shape ######### · example 180100228 · confidence medium

Year

digits 1-2 (YY) -> 2018

Week or month

month = digits 4-5 -> Oct

Plant

digit 3 unexplained

Example: serial 180100228 decodes to October 2018.

1985 to 2012 formatVERIFIED

Shape AA#### · example UJ1087 · confidence high

Year

letter 1: A=1985/2010 B=1986/2011 C=1987/2012 D=1988/2013 E=1989/2014 F=1990/2015 G=1991 H=1992 J=1993 K=1994 L=1995 M=1996 N=1997 O=1998 P=1999 Q=2000 R=2001 S=2002 T=2003 U=2004 V=2005 W=2006 X=2007 Y=2008 Z=2009 (I skipped, O used)

Week or month

month = letter 2 (A=Jan..M=Dec, I skipped) -> Sep

Example: serial UJ1087 decodes to September 2004.

before 1984 formatVERIFIED

Shape A####### · example D8367019 · confidence high

Year

digits 2-3 (YY) -> 1983

Week or month

month = letter 1 (A=Jan..M=Dec, I skipped) -> Apr

Example: serial D8367019 decodes to April 1983.

Where the data plate is on a heat pump

On the outdoor unit, same place as a condenser: a plate on the side or back of the cabinet near the line set. The indoor air handler carries its own plate with its own serial.

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 Heat Pump at 10 to 15 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.

What we could not confirm

• Three styles: 2012+ numeric YY?MM..., 1985-2012 letter-year + letter-month (A-F reused for 2010-2015), pre-1985 month letter + YY. warranty.waterfurnace.com = 200 (dealer/owner warranty portal; serial lookup mechanics not confirmed). waterfurnace.com/warranty 404.

Sources

• https://www.building-center.org/waterfurnace-hvac-age/
• img: WaterFurnace-HVAC-style-1.jpg
• img: WaterFurnace-HVAC-style-2.jpg (transcribed)
• img: WaterFurnace-HVAC-style-3.jpg (transcribed)
• https://warranty.waterfurnace.com/official

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