Water Heater Age ID by Serial Number
- Adam Garrett
- Dec 5, 2022
- 1 min read
Updated: Mar 21, 2024
Often if agents look at the serial plate of main systems, and don't see the age clearly labeled on them, they will leave it to home inspectors to determine. That's not necessary, as you'll see below with a quick reference guide to some of the most common water heaters and a link to more water heater information. For brevity & what's most important, I'm only focusing on the year of manufacture. See the hyperlinks for additional details on the week/month/other information.
Disclosure on Limited Accuracy
Keep in mind that I have seen where following the online charts can lead you in the wrong direction before. I find them to be >95% accurate. Click on the hyperlinks for higher level of accuracy, but if 2 charts vary, look for more charts. It's best to look at more than one source including but not limited to the manufacturer & a home inspector, in addition to the below chart, for the highest level of accuracy. In the event that you ever see inaccurate information on this list, please let me know.
Sources are hyperlinked on each row. For a more comprehensive list, go to Building-Center.org's list here. I found their lists to be more accurate/user-friendly than others, though you'll have to do more digging than the guide below since they don't publish a quick reference chart like this one.
Year by Serial # Below (most often 1st 2 numerical digits, w/ some 3rd-4th numerical digits & some lettering systems
American water heater company (1st 2 digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) |
1st 2 yr | Style 1: 05035 35368 Style 2: 1924115263020 |
AO Smith (1st 2 numerical digits)
Bradford White (see chart)
manufacturer | Which Digit Focuses on Year | Style Patterns (yr in blue) | Lettering system |
DG6322957 OA822685 | 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 OA. 1997 P. 1997 or 2017 S. 1998 or 2018 T. 1999 or 2019 W. 2000 or 2020 X. 2001 or 2021 Y. 2002 or 2022 Z. 2003 or 2023 |
Craftsmaster (1st 2 digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | ||
0020118002 | | |
Envirotemp (1st 2 digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | ||
043812019 | | |
GE (3rd-4th numerical digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | ||
3rd-4th numerical digit is year | Style 1: 1108903259 Style 2: GE 09022246884 Style 3: GENG 0601D13586 Style 4: RN0197147899 | | |
Kenmore (1st 2 numerical digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | ||
Style 1A: A03307353 Style 1B: 800423049 Style 3: 1210A002243 (State style) | | |
Maytag (1st 2 numerical digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | ||
Style 1: L07A0811460 Style 2: D03108164 Style 3: AJ89123456 | | |
Raywall (1st 2 digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | ||
043812019 | | |
Rheem (3rd-4th numerical digits in tanked styles; 1st 2 numerical w/ tankless)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) |
3-4 numerical in all tanked styles 1st 2 numerical w/ tankless (style 6) | Style 1: R 0884B10488 (Serial Number begins with a prefix - i.e. R; RN; RNG; RHNG; etc.) →Style 2: RHLN 0106534307 (Serial Number begins with a prefix - i.e. R; RN; RNG; RHLN; etc.) →Style 3: A141511869 →Style 4: D1114A441408265A →Style 5: RHNG 0804P000036 (Serial Number begins with a prefix - i.e. R; RN; RNG; RHNG; etc.) →Style 6: 05.05-000021 (Tankless Water Heater) →Style 7: RHUN M181401735 (Serial Number may begin with a prefix - i.e. R; RN; RNG; RHNG; etc.) |
Rinnai (see chart)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) | Lettering system (if applicable to yr) |
A. 1st letter/digit for style 1 that starts w 2 letters B. 1st 2 digits for style 2 that starts w 2 numerical digits | Style 1: BL. CA-051306 Style 2: 04. 03-102521 | Style 1 A 2009 B 2010 C 2011 D 2012 E 2013 F 2014 G 2015 H 2016 J 2017 K 2018 L 2019 M 2020 N 2021 P 2022 R 2023 |
Ruud (3rd-4th numerical digits in tanked styles; 1st 2 numerical w/ tankless)
Styles 1-5: 3rd-4th numerical digit for tanked Style 6: 1st-2nd numerical digit for tankless | →Style 1: RU 0904B21710 (Serial Number begins with a prefix – i.e. R; RN; RNG; RHNG; etc.) →Style 2: RHLN 0106534307 (Serial Number begins with a prefix – i.e. R; RN; RNG; RHNG; etc.) →Style 3: A141511869 →Style 4: D1114A441408265A →Style 5: RHNG 0804P000036 (Serial Number begins with a prefix – i.e. R; RN; RNG; RHNG; etc.) →Style 6: 05.05-000021 (Tankless Water Heater) | |
State (1st 2 numerical digits)
manufacturer | which serial #s for age (focus on year; "numerical digits" excludes alphabetical) | Style Patterns (yr in blue) |
1st 2 numerical digits | Serial number styles/formats found are: Style 1: 1210A002243 or S1318 F000046 Style 2: H765662231 or M07A009387 Style 3: AF04A093001 Style 4: 1735107397129 |
More
For many more water heater brands by 1st letter, go here.
What Size Water Heater do I Need?
The Department of Energy has a solid resource on this subject. It includes but is not limited to the following for tank-based water heaters:
"To properly size a storage water heater for your home... with a tank -- use the water heater's first hour rating. The first hour rating is the number of gallons of hot water the heater can supply per hour (starting with a tank full of hot water). "
Image courtesy Department of Energy
While the above table might be an average and can be useful, it's also important to consider factors like how long of showers you take, do you take baths, do you use the full force of your shower when taking a shower or is there a way to lower pressure without changing the temperature, do you have built-in controls to diminish the maximum flow like I have at my home, etc. Diminishing shower flow can help you cut costs (in most cases, i.e. all paying for their own water and the heating source), increase the lifespan of your unit, help the environment, and have a positive impact on what water heater size you'll need. If you find that you run out of hot water, rather than jumping to replace it, consider options to diminish water flow and to space out showers between people.
If you're willing to pay more to go green, consider a solar water heater or a recirculating shower. According to Rainstick, "recirculating showers typically use small amounts of water and circulate in real-time to avoid single use of water and wasted ingrained heat. The systems often deploy a pump, levels of cleansing, and are not limiting the flow because the water is being re-used."
Water Heater Lifespan per HUD
Description | Family Typical Lifespan | Elderly Typical Lifespan |
External tankless heater, gas or electric | 20 | 20 |
Solar hot water | 20 | 20 |
Residential hot water heater, gas or electric | 12 | 15 |
Flue, gas water heaters | 35 | 35 |
Water Heater Cost (Typically $900-$5400 Installed, but $1.4k average)
Forbes total Cost range | Home Depot Cost Guide |
$900-$3000 Installed, but $1.4k average (2024) |
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