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How to Determine the Age of Your Water Heater


Posted: Jul 31, 2019

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Predicting how long your water heater will last can be difficult — depending on the model and fuel source, its lifetime could be anywhere between 8 and 20 years. Common conventional electric water heaters tend to last 10–15 years, and typically come with a standard six-year warranty.

If you don’t know the age of your current unit, it’s worth checking to see if you’re nearing time for replacement. It pays to prepare before your water heater gives up or fails, which can be inconvenient (at best) or catastrophic (at worst).

Since finding the date of installation isn’t always straightforward, we came up with the handy guide below to help you decode your water heater’s serial number.



Check the label

Check for a manufacturer label on the side of your water heater — this should include the installation date.

If the label is missing, or the installation date is not listed, you can use the serial number to determine the age of your unit.

Decoding the serial number

Serial number formats vary by manufacturer, with the installation date placed differently in each case. Check the brand name on your water heater and then use the following guide to determine the age of your unit:

Rheem and Ruud

MMYY****

MM = Month of manufacture

YY = Year of manufacture

Example: 1209D1234 = December 2009

American and AO Smith

2008–present:

YYWW*******

YY = Year of manufacture

WW = Week of manufacture

Example: 16051234567 = 2016, 5th week (early February)

Pre-2008:

*MYY******

M = Month of manufacture

A = January | B = February | C = March | D = April | E = May | F = June | G = July | H = August | J = September | K = October | L = November | M = December

YY = Year of manufacture

Example: 4D051234567 = April 2005

Bradford White

Bradford White’s serial numbers are a little less straightforward. The year of manufacture is noted by the first letter of the serial number, and the month is the second letter.

YM*******

Y = Year of manufacture

A = 1984 or 2004 | B = 1985 or 2005 | C = 1986 or 2006 | D = 1987 or 2007 | E = 1988 or 2008 | F = 1989 or 2009 | G = 1990 or 2010 | H = 1991 or 2011 | J = 1992 or 2012 | K = 1993 or 2013 | L = 1994 or 2014 | M = 1995 or 2015 | N = 1996 or 2016 | P = 1997 or 2017 | S = 1998 or 2018 | T = 1999 or 2019 | W = 2000 | X = 2001 | Y = 2002 | Z = 2003

Note: Bradford White water heaters manufactured 20 years apart will have the same letter designation

M = Month of manufacture

A = January | B = February | C = March | D = April | E = May | F = June | G = July | H = August | J = September | K = October | L = November | M = December

Example: KH6511396 = August 2013

Is your water heater’s brand not listed above?

If your water heater’s brand isn’t listed, check NACHI’s or The Water Heater Hub’s serial decoder to learn more.

Due for a replacement?

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If it’s time for your old unit to go, consider upgrading to an electric heat pump water heater. The super-efficient heat pump technology can save a three-person household up to $300 a year on utility bills, plus heat pump water heaters come with a standard 10-year warranty. Many utilities also offer installation rebates — check yours here.

Learn more and find a retailer near you

What are Tiers?

Energy efficiency levels and features of heat pump water heaters vary by product tier. Higher tier products have greater efficiency and the more advanced product features.

Learn More

The higher the energy factor, the more efficient the water heater.