Here we explain how to determine the age of a water heater, we provide a chart that decodes the year of manufacture of water heaters, and we discuss the conditions, maintenance, and factors that affect how long a water heater can be expected to last.
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Our photo at page top shows an oil fired water heater with a backpressure problem and other safety concerns like a missing extension tube on that relief valve, and maybe a missing draft regulator and perhaps an oil line that is not protected from damage.
[Click to enlarge any image.]
The data tags (containing the water heater's age) for this heater are hidden by its insulating blanket. Readers who need to determine the age of air conditioning and heat pump equipment should see A/C DATA TAGS.
How can we determine the age of a residential water heater? By looking at and decoding data on the water heater's label.
Nearly all modern water heaters, electric, oil fired, or gas fired, include data tags and stickers that indicate the year and month of manufacture of the water heater.
That doesn't tell you exactly when a water heater was installed in a particular building but it does indicate the age of the water heater itself.
However some manufacturers encode the year and month of manufacture of their water heater in the product's serial number so that the water heater age is not immediately obvious.
Our photo (above left) shows a gas-fired Rheem™ water heater. The label containing the unit's serial number is probably at the water heater top left. The label above the gas control at the water heater bottom typically contains water heater lighting instructions.
For an encyclopedic reference including manufacturers, history, contact information, and serial number decoding we recommend this book.
Scott LeMarr has generously shared his free WATER HEATER AGE DETERMINATION CHART that decodes both furnace age and water heater age. He includes data for many brands of water heater, including hot water systems produced by the manufacturers listed just below. [PDF linked to return here. You can also use the "BACK" button on your browser to return to this page at InspectAPedia.com.]
Water heater age is encoded in data on the information label on these water heaters: Ambassador water heaters, American water heaters, ACE water heaters, A.O. Smith water heaters, Apollo, Aqua Temp, Aqua Therm, Best water heaters, Bosch water heaters,Bradford White, Cafos, Champion, Crosley, Energy Saver, Envirotemp water heaters, GE water heaters, Glascote water heaters, Golden Knight water heaters, GSW, Hotpoint water heaters, JC Penny, Jetglas, JW or John Wood, Kenmore water heaters (Sears Brand), Lochinvar, Lowes, Mainstream, Maytag water heaters, Montgomery Wards, Knight, PermGlas, Reliance water heaters, Revere, Rheem water heaters, Rheem/Rudd/Richmond water heaters, Rinnai, Security, Shamrock water heaters, Standard water heaters, State/Reliance/Sears brand water heaters, Thermo-King, Vanguard water heaters, US Craftsmaster, US Water Heaters, and Whirlpool water heaters.
Mr. LeMarr has also shared
his FURNACE AGE DECODING CHART with InspectApedia readers. [PDF linked to return here.
You can also use the "BACK" button on your browser to return to this page at InspectAPedia.com.]
Our photo (at above left) is from the A.O. Smith EnergySaver water heater in our laboratory. Enlarging this image you will see a date 12/26/02.
[Click to enlarge any image]
Scott points out that
On occasion there is a yellow "Energy" label on the unit and at the bottom (sometimes middle) will tell you what ANSI Spec it was built to or it may give you an estimated cost on a particular year. If it reads ANSI Spec 1994 that it would have to be 94 or newer typically these specs come out every 2-3 years.
The unit's serial number, MM02-2147713-260 identifies the model and its date of manufacture. The "02" following MM indicates that this unit (in our laboratory) was manufactured in 2002 and the -2 following the MM02- decodes to February.
In a second water geyser age (cylinder age, water heater age) example, Rheem water heaters provide first the month MM and then the year in the first four digits of the water heater's serial number.
The label shown here includes 0884 at the beginning of the serial number - August 1984.
For page speed & reader convenience we moved this topic to a separate article - at WATER HEATER COMPANIES by country: Australia, New Zealand, USA, UK etc
While the most complete water heater age de-coding charts and tables are in the book and PDF files we list above, here we also list water heater age or serial number decoding charts for particular water heater brands or products requested by readers.
Note: because some water heater manufacturers (such as American) produce heaters (or calorifiers or cylinders) sold under multiple brands, you may also find your water heater's age decoder by using your browser's On-Page Search feature (Ctrl-F or CMD-F).
For example, Ace, Apex, Aqua Temp, Aqua-Therm ... Tru-Value, Whirpool and more brand names are all produced and decoded by the American Water Heater Age Decoder. There you'll find a complete list of brands or trade names produced by American. So you can find your brand using the on-page browser search feature.
Check the serial number, not the model number.
If you TruFlo water heater was made by American (Tru-Test or Tru Value water heaters) or by U.S. Craftsmaster, then the age is encoded in the serial number as follows:
First two digits of the serial number are the year
Second two digits of the serial number are the week
Example: 9201nnnnn would translate as 1992, first week [i.e. January 1-7 in 1992]
American brand water heaters may be distributed under any of the following names:
Ace Hardware, American Hardware, America's Best, Apex Water Heaters, Aqua TempWater Heaters, Aqua ThermWater Heaters, Aquamatic,BestWater Heaters, Best DeluxeWater Heaters, CraftmasterWater Heaters, De-LimerWater Heaters, DeluxeWater Heaters, EagleWater Heaters, Earl's Water Heaters, Envirotemp Water Heaters, Four-Most Water Heaters, Hotmaster Water Heaters, Hotstream Water Heaters, King Water Heaters, Master Plumber Water Heaters, Nationaline Water Heaters, Neptune Water Heaters, Penquin Water Heaters, Polaris water heaters, Prestige Water Heaters, Pro-Line Water Heaters, Quake Water Heatersr, Quick-Flo Water Heaters, Raywall Water Heaters, Revere Water Heaters, Riviera Water Heaters, Sands Water Heaters, Sentinal Water Heaters, Servistar Water Heaters, Shamrock Water Heaters, Standard Brand Water Heaters, Super-Eagle Water Heaters, Super-Flo Water Heaters, Supreme Brand Water Heaters, Sure-Fire Water Heaters, Thoro-Clean Water Heaters, True-Test Water Heaters, Tru Value Hardware Water Heaters, U.S. Craftmaster Water Heaters, U.S. Supply Water Heaters, Whirlpool Brand Water Heaters, XCL Energy Water Heaters.
A.O. Smith Water Heater Age Determination - reader comment: (May 11, 2012) AO Smith employee said: To tell the age of any AO Smith water is the first 4 numbers. The first 2 are the year and the second 2 are what week it is. I work in the Q.C. Department there and make the serial plates all the time. Hope this information helps some people out - A.O.S. employee.
Example: Ser# 9902123445 decodes to the year 1999 and the week 02 - or early January.
Other AO Smith water heaters that may be sold under different brand names include Glascote water heaters, National water heaters & Perma-Glas water heaters.
Bradford White water heater age is encloded as two letters in water heater's serial number as follows:
Beginning with A = 1984 (or for newer water heaters made after 2003, A = 2004)
Ending with Z = 2003 or M = 2015
Later model water heaters may replace letters with an actual year and month encoding as numeric digits.
Beginning with A = January and ending with M = December
Example: Bradford White water heater serial number ZJnnnnnnn = 2003, September \
Chrysler Air Temp Water Heater Age Query: (Mar 16, 2012) Dan said: Need to find age of Chrysler Airtemp Gas Furnace: Model #4208-10, Ser #'s hard to read. Could be: Ser# 00584865, 06584865, or 0G584865
Reply: best guess 1970.
Chrysler Air Temp Products: see AirTemp and Fedders. In HVAC serial numbers the first digit is a key to the year of manufacture beginning with 1970. So SN# 42599229 would de-code to be manufactured in 1974
Envirotron Water Heater Age Query: (Nov 7, 2011) Jackie said: I need warranty information also. Product #0726021 Serial #0214115365 model #GIF4034T3NV . It's an Envirotemp water heater. Need to know if it's still under warranty.
Reply: Year 2002, week 14. Details are at ENVIROTRON WATER HEATER AGE
2016/02/09 firstname.lastname@example.org said:
Can you tell me the age of a water heater with Model number 52-E-LD-5 Serial number 41464? It has finally given out and needs to be replaced. I'm just curious about to how old it is. The information on the front says Republic Thermo-glas, and mfg. tag says Fowler Manufacturing which I understand is, or was, a division of Republic.
As I'm on assignment out of the U.S. I don't have Carson Dunlop's water heater age decoder at hand. Sorry. Fowler produced both electric and gas fired water heaters until the late 1960's. But the Fowler Manufacturing's Republic Thermo-Glas is not a brand for which we have a decoding chart. I GUESS from what we know of the Fowler Water Heater company history and the serial number on your unit that it was made in April of 1964. That's based on looking for a reasonable two digit year in the number and guessing that the manufacturing month precedes it.
Fowler electric water heaters are dated as early as 1917 and continued into the 1960's. Patent research and trademark research give us some of these dates as well as the originator, Paul L. Fowler who is cited his 1958 patent for a concentric gas and air burner for water heaters, U.S. Patent No. US2564358 A filed in 1947.
Republic Glass-lined "Thermo-Glas" rust resistant water heaters may have been a re-brand of Fowler products. Republic brand electric water heaters were sold at least into the 1960's based on a screen of advertrisements archived by Google. It's possible that the actual water heater tank was produced by Republic Steel Company that in turn was purchased by Rheem Manufacturing in the 1930's.
QE Furnace Age Query: (Nov 18, 2012) Lyn said: I am trying to determine the age of my electric f.a. furnace. It is a General Electric made in Toronto, Ontario.
The Serial number is Ser# 398 870 T21
The model number is BWL730G172B.
If someone could please advise the age of my furnace, it would be greatly appreciated.
Thanking you in advance.
Reply: You've sent us a warm air heating system code not a water heater code. This article and comment page are for water heaters. For details on age determination for heating boilers & furances see AGE of HEATERS, BOILERS, FURNACES.
But I make this code as March 1998
For a complete guide to GE or General Electric HVAC and other equipment you will need to see the pages of data on GE found in Carson Dunlop Associates comprehensive Technical Reference Guide. Generally for GE water heaters the first one or two digits are the month and the next two the year of manufacture. So your heater was made in month 3 and in year 98 - March 1998.
Data tag details: pending; images of Giant water heater data tag wanted. Use our page bottom or top CONTACT link - Ed.
I am not sure I have come to the right place however are you able to tell me where I could find a 2006 Giant Electric Water Heater Manual for Model 172ETE-3F5m? - Anon in Toronto, Ontario, by private email 2016/07/27
Giant electric water heaters are manufactured by
Usines Giant Factories, Inc.,
40 Avenue Lesage
Montreal-East, Quebec, Canada H1B 5H3
The company has a "literature request" page at http://www.giantinc.com/english/literature.htm
The Giant 172 series water heaters, aka "Super Cascade" are
described by http://www.giantinc.com/tech-data/GI-PB019En.pdf
and by http://www.giantinc.com/tech-data/GI-PB045En.pdf
The company's engineering data sheet tells us that a Giant water heater Model 172ETE - 3F5m is not listed but the company currently lists a 172ETE-3F7M as a 74 gallon (279L) or 61 imperial gallon electric water heater using 4500W 240V.
Here is the company's link to the Installation Manual for the Giant 17E heaters: http://www.giantinc.com/tech-data/GI-IM017En.pdf
I am attaching a link to a typical Giant electric water heater installation and operation manual
http://inspectapedia.com/plumbing/Giant_Water_Heater_Manual_GI-IM017En.pdf [PDF about 16MB]
GSW Water Heater Age Query: (Mar 1, 2013) Lee Harding said: I'm trying to determine the age of my GSW hot water heater. Model 6G505DE1
Serial # 50704 535391. I can't tell from these numbers.
Reply: best guess: week 50 of year 1970
Normally the first tow digits of the serial number give the heater's year of manufacture. Your serial numbers don't match this system, perhaps because of wear or smearing or heater particulars. From your serial number we'd guess week 50 year 1970 - which seems a bit antique. Re-check that you're really seeing a 50 in the first two digit positions.
Typically on a GSW Water heater the age is encoded as the first four digits of the serial number as two digits of year followed by two digits of month.
Hoyt Water Heater Age Query: (Nov 5, 2012) Alexandra said: I am trying to find the age of my Hi Test Hoyt water heater. The Serial is SN A87RNH1373190, model A40HM
Reply: best guess 1987. Details along with contact information for Hoyt water heaters are at HOYT WATER HEATER AGE
[Click to enlarge any image]
... here is a photo of my hot water heater data: here is a photo of my hot water heater data:
It still works fine. I don't understand how it can produce 50 gallons for its size. We wanted to move it over 1 inch to accommodate a new washing machine but it appears bolted to the floor. I hate to mess with something that appears to be working fine but worry about the day that it stops. - Anonymous by private email 2016/07/19
Hotpoint water heaters prior to about 1980 such as those bearing the data tag shown above use serial numbers in the format AAAWWYY
Your Hotpoint water heater data tag serial number looks like 1TU2270 leading me to guess that the last two digits may be the year of manufacture (70 in this example). The preceding two digits (22 in this example) may be the week of manufacture.
Looks like this Hotpoint water heater or calorifier was made in 1970? Is that possible?
Later Hotpoint water heaters, manufactured by Rheem, use serial numbers in the format AAMMYY123456 begin with two letters (in position AA)
then follow with two digits of production month (in position MM and numbered 01-12)
followed by two digits of production year in position YY.
The Hotpoint water heating calorifier or cylinder Catalong No. (or model number) is 100WBSC521035, leading me to guess that the catalog number, giving water heater features, decodes as follows:
Last four digits give the wattage of the top and bottom heating element as 35 = 3500 Watts, and 10 = 1000 Watts.
The data tag also indicates
Bolted to floor - sounds as if you're in an earthquake zone. A bit of unbolting, re-plumbing, and then re-securing the heater to the structure would be required. A bit of work but perhaps justified if that's where you need to place your new washing machine.
Hydraulics encodes the date of manufacture as two digits of week and two of year in positions 1-4 of the serial number
Intertherm Water Heater Age Query: Hi, can you tell me the date an Intertherm water heater was made?
Model #IHMS960E4 - Serial #K07433029
Reply: best guess 1974. Details and contact information for Intertherm water heaters are at INTERTHERM WATER HEATER AGE
On Marathon water heaters the age is encoded as the first four digits of the serial number.
Marathon water heaters are currently (2015) a Rheem product.
Wards Water Heater Age Query: 01/24/2014: G M Wagner said: Montgomery Ward Electric Water Heater-Model 94-SHT-2861A, Serial # TE22780' . Would you please tell me how old it is. Remodeling the basement and finally putting in a new one. thank you.
Reply: 1980. Details and contact information for Wards water heaters are at MONTGOMERY WARD WATER HEATER AGE
(Oct 26, 2012) meme said:
how many years should a Rheem hot water cylinder last
Meme, Rheem's warranty period for hot water heating equipment (cylinders, geysers) varies by product series but is typically 5-10 years. You will need your product name and model number as well as serial number to look up the exact information for your unit. For example, the HPWH has a 10-year tank leak warranty and a 10-year parts warranty and a first year in-home labor warranty is included as well.
Some Rheem heating equipment such as gas furnaces includes longer periods for the heat exchanger, such as 20 years or "lifetime".
You should be sure to register your hot water cylinder at the company's website as that will aid in any future warranty claim. You can call Rheem directly for help. In North America call 1-800-621-5622 and listen for the prompt to take you to warranty information provided by the company
Rhyeem serial numbers on modern heating equipment can be decoded by mapping the corresponding digits of the unit's serial number as follows:
MM = month of manufacture
YY = year of manufacture
P = plant identifying code
nnnn = a consecutive serial number for your individual unit
Rheem water heaters that may be sold under other brand names include
AquaTherm water heaters, General Electric water heaters, Hotpoint water heaters, Professional Brand water heaters, Vanguard water heaters & Western Auto water heaters.
- http://globalimageserver.com/FetchDocument.aspx?ID=682d9e43-35ec-48e9-b3f7-1a41d328375d retrieved 6/24/2014
Ruud water heater serial numbers encode the heater age in the first four digits of the serial number as
Other Ruud water heaters that may be sold under a different brand name include
Professional Water Heaters.
State water heaters, produced by State Industries, encode the age in the first three positions of the State water heater serial number as
Where M is the month encoded corresponding to A = January through M = December and the second two digits are the numeric year.
Or on some State water heaterrs age is encoded in the firsrt four positions of the State or Apollo Comfort Products Water Heater serial number as
Other water heater brands by State or using the same format include
Apollo Comfort Products water heaters
U.S. Craftsmaster water heater age is usually encoded in the first four digits of the heater's serial number as in this example:
Where WW is the week number (weeks 01 through 52) and of course YY indicates the last two digits of the year of manufacture.
U.S. Craftsmaster is an indpendent water heater manufacturer whose heaters have been sold under the following trade names or brand names
Ace Water Heaters, Ace Hardware Water Heaters, American Hardware Water Heaters, America's Best Water Heaters, Apex Water Heaters, Aqua Temp Water Heaters, Aqua Therm Water Heaters, Aquamatic Water Heaters, Best Water Heaters, Best Deluxe Water Heaters, Craftmaster Water Heaters, De-Limer Water Heaters, Deluxe, Eagle Water Heaters, The Earl's Energy Conservation Water Heater, The Earl's Energy Saver Plus Water Heaters, Envirotemp Water Heaters, Four Most Water Heaters, Hotmaster Water Heaters, Hotstream Water Heaters, King-Kleen Water Heaters, King-Line Water Heaters, Master Plumber Water Heaters, Nationaline Water Heaters, Neptune Water Heaters, Penquin Water Heaters, Prestige Water Heaters, Pro-Line Water Heaters, Pro-Line Plus Water Heaters, Quaker Water Heaters, Quick-Flo Water Heaters, Raywall Water Heaters, Revere Water Heaters, Riviera Water Heaters, Sands Water Heaters, Sentinal Water Heaters, Sentinel Water Heaters, Servistar Water Heaters, Shamrock Water Heaters, Special Deluxe Water Heaters, Standard Water Heaters, Supereagle Water Heaters, Super-Flo Water Heaters, Supreme Water Heaters, Sure-Fire Water Heaters, Thoro-Clean Water Heaters, True-Test Water Heaters, Tru Value Water Heaters, Tru Value Hardware Water Heaters, U.S. Craftmaster Water Heaters, U.S. Supply Water Heaters, Whirlpool Water Heaters, XCL Energy Saver Water Heaters
Weil McLain Heater Age Query: (Oct 25, 2012) carl said: how do you find an age of a Weil Mclain GV 3 Gold serial no cp 3406659
Reply: this looks like you have sent us a heating boiler brand and model number not a domestic water heater. Quoting product literature:
The Weil McLain GV boiler is a high efficiency, gas-fired direct vent water boiler with cast iron sections. Using sealed combustion technology, the boiler reduces energy usage by eliminating air infiltration. The GV boiler is easy to install and service, and is useful for a wide variety of applications including residential, light commercial, multiple boilers, indirect-fired water heating, and radiant heating. - pexsupply.com
From Carson Dunlop Associates Technical Reference Guide, the most complete HVAC and water heater age decoding guide I've got (provided courtesy of CDA), Weil McLain heating boiler serial numbers beginning with 34nnnn were manufactured between 1998 and 2000.
This article and comment page are for water heaters. For details on age determination for heating boilers & furances
see AGE of HEATERS, BOILERS, FURNACES.
Watch out: for other Weil McLain boiler numbers one needs to consult the Guide cited above, as the encoding of serial numbers does not afford a formulaic de-code procedure. For example Weil McLain boiler serial numbers beginning with 32nnnnn were made beginning in 1997.
Home inspectors typically expect a generic water heater to last about ten years. However all of us have found 20 year old models still going strong, while on occasion a newer model fails early.
Details about water heater life expectancy: We have expanded and moved this topic to WATER HEATER LIFE
Type of water heater tank and water heater warranty - modern "glass lined" water tanks are coated to resist corrosion. The manufacturer's warranty is a clue to how long the company expects their water heater tank to last.
Typical water heater warranty periods for a water heater installed for use by a single family are 6-years, 9-years, or 12-years.
But beware: if the water heater tank leaks and fails before the end of the warranty period, if the system has not been properly installed or maintained the warranty may be void.
Water heater warranties typically indicate that the tank is warranted against leaks due to rust, corrosion, or chemical action of the water but the warranty will exclude warranty coverage for the geyser or water heater for
Continue reading at WATER HEATER LIFE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
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(Oct 11, 2011) sharon said:
need to know about tank warranty
The warranty period and terms of your specific water tank depend on its model, age, and of course proper installation. Typically you can find that information in the installation manual and papers for your unit, or if you don't have that information, you'd contact your heater's manufacturer and give them the model and serial number of your water heater.
(Feb 11, 2013) B Skiba said:
We are worried about our hydronic water heater. Our neighbors had severe water damage when their water heater had a major leak while cold water kept flowing into the heater. Their system is similar to ours. We are going on vacation and wonder if we can turn off the cold water intake so that if the water tank develops a leak, at least we won't have a flood. Can we do this safely?
(Feb 26, 2012) Karen said: I want to know the year of my hot water heater
(Nov 5, 2012) Alexandra said: I am trying to find the age of my Hi Test Hoyt water heater. The serial is A87RNH1373190, model A40HM
(Dec 30, 2012) donna said: trying to find how old water heater is model# 71-40db seaial# rh0900b06241
(Feb 5, 2013) wells said: 64 gal model EXR90-52
(Mar 1, 2013) Lee Harding said: I'm trying to determine the age of my GSW hot water heater.Model 6G505DE1
Serial # 50704 535391. I can't tell from these numbers.
(Mar 21, 2013) beckett said: how do i tell the age of my hot water tank
You can often find the year and month encoded in the product serial number, as we describe in the article above.
(Mar 29, 2013) Anonymous said:
how old is an Envi-ro-temp water heater model#mhe2e30hs035v serial # 9812126163 product# 0820183 Thank you, Cheryl Satterwhite
If we assume that your Envi-ro-temp water heater is an Envirotron product I can give this information from CDA's technical reference cited in our References section:
Envirotron went out of business around 1980 - which would your heater at least 33 years old. The current incarnation of the Envirotron name is a company that provides "green technology education and resources" and has their own website with that name.
There is also Solatherm-Envirotron, 1983
Solar Hot Water System for a Newspaper Building: Final Report
Solatherm Envirotron, 1981 [book about 151 pages)
This company published a number of solar water heater studies and documents.
Is your heater a solar unit?
In any event, from the serial number serial # 9812126163 I would bet your heater was made in year 98, month 12, or December 1998.
Details are at ENVIROTRON WATER HEATER AGE
Questions & answers or comments about how to find out the age of a heating appliance: water heater, heating boiler, heating furnace.
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