Photograph of an air conditioning system data tag or sticker showing the manufacturer's specifications Air Conditioning & Heat Pump Data Tags
Data-Tag Decoders: BTUs, Tons, Equipment Age

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HVAC data tag decoding: This article explains and translates all of the data found on information tags and stickers used on air conditioning and heat pump equipment. This article series answers most questions about air conditioning systems.

This article provides help in decoding air conditioner, boiler, furnace, heat pump, water heater data tags and determining the age, model, or specifications of that equipment.

Find and read the data tag on air conditioners or heat pumps to determine Air conditioner BTUs, Tons, Age: decoded on data tags. Air conditioner electrical requirements & refrigerant needs. Air conditioner cooling capacity coded in model numbers. Air conditioner and heat pump manufacturer's information; serial number gives A/C age.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

A/C DATA TAGS - Air conditioner & heat pump data tags de-coded

Photograph of the information sticker from a residential air conditioning compressor unitHere we explain the meaning of each of the data names and contents of typical air conditioner system data tags. We include examples of how to make use of the data to estimate equipment age, capacity, and even its condition. (Not all of the terms we define below will appear on all equipment or motor tags.)

The photo at page top shows the main data sticker from a 1997 split system air conditioning compressor/condenser unit.

[Click to enlarge any image]

This model, made by Sanyo, Inc., provides easy-to-read basic data about the system including its year of manufacture, refrigerant, electrical requirements, and service information.

Article Contents

What Information is Provided by a Data Tag on an Air Conditioner or Heat Pump?

The photo shown above is for a conventional (non-split) residential air conditioning compressor unit.

Unless it has been painted-over or lost, on most air conditioners and heat pumps, a metal, foil, or plastic tag or data sticker is usually affixed to the outdoor air conditioner or heat pump compressor/condenser housing.

Depending on the age and equipment manufacturerthe format and content of data on this tag varies, but typically the tag will allow you to discover some or all of the considerable amount of data listed here:

How to estimate air conditioner size (C) Carson Dunlop Associates

Energy Guide Sticker for Carrier High Efficiency Gas Furnace (C) Daniel Friedman

Modified, damaged, or torn air conditioning equipment information data tags can make age, capacity, and repair of any equipment more difficult. For the air conditioning compressor unit shown here, all we know is that the manufacturer was Singer. Model numbers and serial number appear to have been cut away from the data tag. Why?

Sometimes when equipment data labels are removed or obscured a building buyer or a home inspector may raise a concern that the unit installed was different than that which the was ordered or that it is of questionable origin. On rare occasion that might be the case..

AC data tag (C) InspectApedia.comBut Ratib Baker, a member of member of Refrigeration Service Engineers Society (RSES), informs us that during the 1980's HVAC equipment manufacturers used a type of label which lacked UV resistance, faded, cracked, and eventually peeled away from the equipment, making equipment identification and ordering of replacement parts difficult.

Mr. Baker wrote (October 2008) that in the 1980's "the [HVAC compressor] label's protective mylar surface was damaged by the printing of the model and serial numbers and the electrical data which allowed the UV from the sun to destroy those areas.

Upon discovering that they did not stand up to weather, most manufacturers started putting a second label inside the electrical compartment. Eventually better labels were designed, but some of the better manufacturers still put a second label in the unit."

Where a data tag or label on equipment is damaged or missing, check further for more label data including inside the unit's enclosure.

Service technicians may have written the model and serial number data in indelible marker, or the manufacturer may have provided a second data label inside the unit - check HVAC equipment with lost or damaged labels to see if you can find that data elsewhere.

You may also find equipment identification details in the installation and service manuals for the equipment if those have been kept in the building. Look around the indoor equipment for those documents.

What we can say from the label in the photograph above is that by 2007 when the photo was taken by an ASHI inspector, this particular equipment was at least 23 years old - older than its usual anticipated life expectancy: the Singer brand On air conditioners was dropped in 1984.

Alphabetical List of HVACR Air Conditioning & Heat Pump Equipment Data Decoders

Here we focus on decoding the age of some HVACR equipment by finding that in the device serial number. Often the heating or cooling capacity is also encoded as a number (thousands of BTUs/hour) or a letter that decodes to a number. Details are in the age decoder guides given above.

Often you will find very detaild data tag decoding help for your specific brand and model air conditioner or heat pump by consulting its manual.

See MANUALS & PARTS GUIDES - HVAC - alphabetical list of manuals & guides sorted by manufacturer, free downloads

Alphabetic Index to Data Tag Decoders by Brand

A  -  B  -  C  -  D  -  E  -  F  -  G  -  H  -  I  -  J  -  K  -  L  -  M  -  N  -  O  -  P  -  Q -R  -  S  -  T  -  U  -  V  -  W  -  X  -  Y  -  Z


Amana Air Conditioning Data Tags

The year of manufacture is encoded as a letter in the serial number.


B = 1971 / 1981 / 1991 / 2001 etc.

L = 1972 / 1982 ... etc

A = 1973 ... etc

C = 1974 ... etc

K = 1975 ... etc

H = 1976 ... etc

O = 1977 ... etc

R = 1978 ... etc

S = 1979 ... Etc

E = 1970, 1980, etc.


Bryant Air Conditioner Data Tag Age Decoder

After 1979, the week of production is encoded in digits 1 & 2 of the serial number, and the year of production is encoded in digits 3 or 3&4 of the serial number.

Eg. 5214AX31929 decodes as week 53 of 2014

WWYAX12345 decodes as follows

WW = sequential week within year, 01-52

Y = year as follows

R S T U V W X or Y = 1964 -> 1971 (e.g. S = 1965)

A B C D E F G or H = 1972 -> 1979


Carrier Air Conditioner or Heat Pump Age Decoder

Carrier air conditioner data tag (C) Daniel Friedman at[Click to enlarge any image]

Also see Carrier contact information and manuals at CARRIER Air Conditioners, Boilers Furnaces

Carrier 1980-present: week and year are encoded in the first four digits of the serial number as WWYY1234567

Carrier equipment produced in the 1970's MY12345678 encoded the month and year as a letter (month) and single digit (year) where A=January -> M = December. e.g. A9xxxxxx = January 1979

Carrier equipment produced in the 1960's Y123456789 encoded just the year of manufacture as a single digit (year) in the first position of the serial number, e.g. 9xxxxxx = 1969.

Reader Question: where is the SEER rating on my Carrier Condenser unit?

(Jan 30, 2014) Kevin said:
I'm trying to find the SEER rating on my Carrier condenser.

Is it supposed to be on the data tag somewhere?


Good question, Kevin, thanks.

No we do not generally see the SEER rating encoded nor explicit on an HVAC equipment data tag. Rather it is in the product literature.

I THINK that a reason for this is that the net SEER rating for a given air conditioner or heat pump depends on how a combination of components operates together while certain individual components might be used in more than one set-up.

Example: Carrier's Infinity Split System air conditioners are rated by the company at SEER 16.5 (Model 24ANB6) to 21 (Model 24ANB1)

BUT for some manufacturers there is a clue to SEER right in the model number. The Infinity Model 24ANB1 is designated with MODEL NAME INFINITY21 while the Infinity Model 24ANB6, rated at a seer of 16.5 is designated with MODEL NAME INFINITY16.

You can for this series only roughly approximate SEER by noting the model name. For example within the Infinity product line by Carrier, two Infinity Models designated INFINITY17 are rated at SEER 18.

Adding honesty to SEER ratings, companies typically state in the product literature "Up to SEER nn" recognizing that the actual energy efficiency in practice and in specific installations will vary.

In advertising law, "up to" claims, to be legally defensible, sport a number that must be met by at least ten percent of actual cases.

In our article on SEER (search InspectApedia for the title

Air Conditioning SEER Energy Efficiency Ratings Explained - HVAC Dictionary

I will add this Q&A and if I can find more details I will elaborate there on where & how to find the SEER of your equipment - thanks again. Daniel

OH - and if you give me the model number I'll dig up that specific seer. Send along a photo of the data tags on your equipment if you can - use the CONTACT link at the top or bottom of any of our pages.

Reader Question: age & data tag decoding for Command Aire equipment

I am looking to replace a 30+ year old cooling/heating wall convector from a New York high-rise apartment unit.

Attached is the current unit in operation, and there a total of four (4) located in separate spaces within the unit.

[Click to enlarge any image]

Command Aire wall convector unit identification (C) InspectApedia DC Command Aire wall convector unit identification (C) InspectApedia DC

Can you please tell me if you know what kind of a unit this is from the poor quality photo (Command-Air(?)), and if there are modern replacements I can look into that possibly can be controlled from a wall plate control next to a light switch (for example). - D.C. 8/21/2014


I'm not what I'm looking at in your photo.

But some basic information about wall convector units used for heating and/or cooling is at


Typically in a high rise apartment the energy source for heating and cooling will be piped from a common building source. You'll want to know what your building supplies before thinking about replacing the equipment.

Reader Follow-up:

The photo was a poor shot of the model label sent by the contractor currently remodeling the apartment. The units are enclosed within a built-in wooden lacquer cabinet, similar to the attached photos show.

I was trying to make out the unit name, and I believe it is an early 80’s Command-Aire model, about 62” wide by 12” deep. I’ve also attached a stand-alone model, with the controls on top beneath the grill.

I’m not sure about the building supply details yet, since I have not received information from the contractor, but I’m just trying to find a comparably model to replace this unit(s). I believe the overall size and top diffuser gives me a head start to look into a Trane Type AK model, just to start comparing.


Command Aire brand was later bought by Trane - so when you know what type and model you've got installed that'd be a place to start looking for a compatible replacement.

When you have a clear image of the unit's data tag you'll see brand, model, serial number that will decode into just what is installed. There's little point in looking for equipment and prices before you know what kind of equipment works with your building's infrastructure.

Coleman HVAC Data Tags

Command Aire Data Tag BTUh Capacity Decoding

For example, Command Aire included heat pumps (which you may not have)
SWPR 261 thru 611 water source heatpumps.
The three digit number following SWPR 261 indiates the unit BTUs

261 = 24000 BTUh
281 = 30000 BTUh
361= 36000 BTUh
411 = 42000 BTUh
511= 49000 BTUh
611= 62000 BTUh

Contact Trane (commercial / residential) at

(800) 945-5884

American Standard Heating & Air Conditioning
Customer Relations
20 Corporate Woods Dr.,
Bridgeton, MO 63044


Command Aire brand was bought by Trane - see Trane under  T  on this page.




Fedders Air Conditioner or Heat Pump Age Decoder

Month and year are encoded as alphabetic letters in the last two positions of the serial number, beginning with A = September and A = 1966


Reader Question: age of a GE air condenser unit

Could you help us determine the age of a General Electric central air condenser.

Model TA36H1F01 S/N 205100925

This unit appears to be extremely old, but would appreciate any help you can give me. - John 6/1/12


John, Carson Dunlop's Technical Reference Guide has several pages of GE equipment data decoding information, including the observation that

beginning in 1944 GE coded the age in the last three digits of the serial number, with the year in the third from last position.

But the GE serial number codes on air conditioners & heat pumps used letters (N-Z = months Jan-Dec) and Year A-Y = 1944-1964, then repeated). Your serial number does not conform to the known codes for General Electric air conditioners. GE used letters not digits for month and year as I explained above.

Is it possible you are mis-reading a letter "Z" as a numeric "2" or a P or R as a "9" and an "S" as a "5" ?

Examples of troubles reading old fuzzy or partly obscured serial numbers or model numbers on HVAC equipment are in our article just above. So if your 2 and 5 are really SS the unit could be as old as May 1959 or perhaps more likely, as recent as 1980.

Send us a sharp focused photo of the entire label if you can and I'll comment further.

The Model Number you provided indicates in the two digits following the TA (TA36) 36,000 BTU/h

GE no longer makes A/C units - heat pumps were sold to Trane, Canada.




See individual product MANUALS & PARTS GUIDES - HVAC as individual device manuals include data tag decoders





KeepRite Air Conditioner / Heat Pump Data Tags

KeepRite is a brand belonging to International Comfort Products, Lewisburg TN 37091 USA Website:

International Comfort Products is part of UTC Climate Controls & Security that is in turn a unit of United Technologies Corporation.

[Click to enlarge any image]

KeepRite air conditioner data tag - International Comfort Products (C) reader KeepRite air conditioner data tag - International Comfort Products (C) reader


Lennox Air Conditioner or Heat Pump Age Decoder

Lennox air conditioner data tag decoder (C) Daniel Friedman at


Since about 1974, digits 3 & 4 indicate year & digit 5 indicates month of production where the months are encoded beginning with A = January

Also see contact information for Lennox and Lennox HVAC manuals for downloading at LENNOX Air Conditioners, Furnaces, Heat Pumps

Luxaire Heating & Air Conditioning Data Tags



Mitsubishi Air Conditioner & Heat Pump Data Tags

Mitsubishi Mr. Slim R410A compressor/condenser label (C) Mitsubishi Mr. Slim R410A compressor/condenser data tag (C)


See individual product MANUALS & PARTS GUIDES - HVAC as individual device manuals include data tag decoders




Rheem Air Conditioner or Heat Pump Age Decoding


Last four digits of the serial number encode week of manufacture and year of manufacture as xxxxxWWYY

Ruud Air Conditioner or Heat Pump Age Decoder


Last four digits of the serial number encode week of manufacture and year of manufacture as xxxxxWWYY


Samsung Mini Split Age Decoder information in data tag

Serial Number : P1BW6XXXXX is translated as P1BYM12345

The 4th Digit is Y or the year of manufacture :

M = 2018 L = 2017 K = 2016 J = 2015 H = 2014 G = 2013 F = 2012 E = 2011 D = 2010 C = 2009 B = 2008 A = 2007 Z = 2006 Y = 2005 X = 2004, W = 2003, T= 2002, R= 2001, N= 2000, K= 1999, J= 1998, H= 1997

The 5th Digit is M or the month of manufacture : 1= Jan, 2= Feb, 3= March, 4= April, 5= May, 6= June, 7= July, 8= August, 9= Sept, A= Oct, B= Nov, C= Dec


Sanyo Split System Air Conditioner / Heat Pump Data Tags

Sanyo split system data tag decoder (C) Daniel Friedman at InspectApedia.copm

[Click to enlarge any image]


Singer Air Conditioner Data Tag Decode

Singer air conditioner data tag, defaced (C)

Watch out: in our OPINION if you encounter HVAC equipment whose data tags have been deliberately cut to remove product identification information you should assume that something fishy has been going on.

See SINGER HVAC Manuals & Parts




Trane Air Conditioner or Heat Pump Age Decoder

Trane XR 13 compressor condenser unit data tag (C) Trane XR 13 compressor condenser unit data tag (C)

Above: Trane XR 13 data tag photographed near Kearney, Kansas

On later model Trane HVAC equipment the year of production is stamped as a four-digit year in the upper or lower right corner of the data tag.

Example 12/2015 decodes to 12 = December 2015 = year of manufacture

Other Trane Serial Number Formats & Decoders

For Trane manuals and specifications and contact information see TRANE AIR CONDITIONERS & HEAT PUMPS


Unitary Products Corp. HVAC Data Tag Decoder

Unitary Products air conditioner heat pump data tag at

The U.S. Unitary Products Group (website ) markets air conditioning and heat pump equipment under the following brands:

See UNITARY PRODUCTS HVAC - for manuals and contact information or see the individual brands listed above.

See also contact information and manual download sources at DAIKIN GLOBAL, Daikin Mini Split A/C, marketed in the U.S. until 1988p

In the U.S. a "unitary" lineup is offered by Daikin in the North American residential market.


Whirlpool Corporation Equipment Data Tag Translator

Whirlpool air conditionre or heat pump data tag translator table

Source: Whirlpool WGPH45 Packaged Heat Pump, Product Specifications [17]

[Click to enlarge any image]

Whirlpool air conditioner and heat pump brand, type, refrigerant, SEER, and other data including heating or cooling capacity in tons is encoded in the model number positions as shown in the illustration above.


The age of Whirlpool air conditioners or heat pumps are encoded in the first four positions of the serial number as a decade and year (one alphabetic digit, one numeric digit) and week of manufacture (two numeric digits).

where Y = Year as follows: G = 1970's, H = 1980's, I = 1990's, J = 2000s, K = 2010s

where WW = week number

Example: J752XXXXX = 2007, week 52.


See individual product MANUALS & PARTS GUIDES - HVAC as individual device manuals include data tag decoders

York HVAC Data Tag Information

York - see YORK INTERNATIONAL AC & HEATER Manuals, York International -

Where to Buy Carson Dunlop Associates' Technical Reference Guide decodes equipment data tags for air conditioners, heat pumps, etc.

Carson Dunlop Associates' Technical Reference Guide (below) provides the most extensive HVAC equipment data tag decoder & other information to determine the age of boilers, furnaces, water heaters, air conditioners, and heat pumps by decoding the product serial number.

HVAC Technical Reference Guide (C) Carson Dunlop Associates

For the most complete and very detailed HVAC equipment data tag and age decoding information anywhere (about 128 manufacturers & brands), Alan Carson and Bob Dunlop, of Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates'

Technical Reference Guide
to manufacturer's model and serial number information for heating and cooling equipment

Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.

Here at we discuss different types of heating systems (OCTOPUS FURNACES, forced air heating systems, STEAM BOILERS, forced HOT WATER BOILERS, high efficiency systems) and fuel types (coal, oil, gas) as an aid in determining the age of a home or other building.

Heat pumps are discussed at AIR CONDITIONING & HEAT PUMP SYSTEMS

The Carson Dunlop Technical Reference Guide provides both equipment data tag decoding data and also manufacturer contact information as well as historical dates for many brands of heating and cooling equipment. Included in the manufacturers listed are also makers of ancillary equipment such as controls, circulator pumps, etc., not just boilers, furnaces, and heat pumps themselves.

References for HVAC controls & switches

Watch out for Confusing or Mis-Reading Letters & Numerals on Old HVAC Equipment Data Tabs

Especially when equipment is old or has been located outside where its data tag can become obscured, faded, or damaged, it is easy to confuse as certain numeric digits some alphabetic characters, and vice versa.

Our table below gives some confusion examples to watch for. So if information about model numbers or serial numbers for a given manufacturer specifies that that company use a mix of alphabetic and numeric characters (E.G. General Electric), and you see only numeric, look again to see if you're making a mistake.

Table of HVAC Data Tag De-Coding Errors

Numeric Character Confused
With alphabetic or numeric
Numeric 0 - zero Alphabetic O
1 I
1 L
2 S
2 Z
3 E (reading upside down)
3 8
5 S
6 9 (reading upside down)
6 G
7 2
8 B
9 6 (reading upside down)

Other information tags and stickers on air conditioners and heat pumps

Service and refrigerant connections

Photograph of a split system air conditioner (C) Daniel Friedman

Service information and/or refrigerant piping hook-up may be provided by a separate sticker on the air conditioner compressor/condenser unit, such as the piping arrangements shown on this split-unit compressor side.

More critical service data such as refrigerant type and operating pressures are recorded in the main data tag shown earlier.

Air conditioner or heat pump basic wiring diagrams

Photograph of an air conditioner wiring diagram. (C) Daniel Friedman

A basic hook-up wiring diagram may be provided by the manufacturer on a separate sticker on the air conditioner compressor/condenser unit such as this one from the Sanyo unit.

Air conditioner or heat pump safety warnings

Photograph of the safety stickers on a residential air conditioning system

Safety warnings for consumers and service people also appear on tags or stickers on modern air conditioning and heat pump units, such as shown in the photo above.

Data information tags on commercial air conditioning and heat pumps

Photograph of a commercial air conditioning rooftop unit sticker indicating cooling or heating capacity as a function of air temperature (C) Daniel Friedman Photograph of a refrigerant charging chart for a commercial air conditioning rooftop mounted unit (C) Daniel Friedman

Commercial air conditioning or A/C/Heat pump units such as the rooftop unit from which these data tag photos were taken often provides additional and critical capacity and service data.

[Click to enlarge any image]

The first or left hand tag shows the equipment's operating capacity in both BTUH and watts, and shows a maximum air temperature at the unit. The second photo at right shows a refrigerant charging chart that must be consulted by the service technician who monitors suction line (low pressure or return line) temperature and pressure.


Continue reading at SEER RATINGS & OTHER DEFINITIONS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see DATA TAGS on AIR CONDITIONERS FAQs - questions & answers about data tags on air conditioners and heat pumps



Or see these

Articles on Building Component Age

Suggested citation for this web page

AGE of AIR CONDITIONERS & HEAT PUMPS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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