Carrier HVAC Age: Serial Number Breakdown for AC, Furnace & Heat Pump

How old is my Carrier AC – or heat pump or furnace? That’s a common question, and it is answered here.

The age is discovered by answering – what’s the date or year your Carrier was made? This page is about decoding Carrier serial numbers to determine the age of a Carrier AC, heat pump or furnace.

When completed, you will know how to read a Carrier air conditioner serial number – or the number for a furnace or heat pump.

Note: This is about reading Carrier serial numbers, not Carrier model numbers, which have an entirely different nomenclature related to equipment type, stages of heating or cooling and the series such as Infinity or Performance.

How to Read a Carrier Air Conditioner Serial Number – or Furnace or Heat Pump

This section is about Carrier AC, heat pump and furnace equipment manufactured in the last 30 years. Older units have a different serial number nomenclature, which is explained later on the page.

It is quite simple to tell the age of your Carrier furnace, AC or heat pump.

Locate the Carrier Serial Number

1. Find the serial number. It should be on a tag or label affixed directly to the jacket of the furnace, heat pump or AC. It looks like this.

2. Locate the Serial Number on the tag. It probably just says “Serial,” before the number.

Decode the Carrier Serial Number – 9 and 10 Digits

OK, now here is how to read a Carrier AC serial number – or the number on a heat pump or furnace.

1. The first two numbers refer to the week of the year. 01 is the first week in January. 52 is the last week in December. The number tells you just the week number – you have to figure out what month that is, if you care to. For an approximation, divide the number by 4, so 17 would be 17/4=4.25, or one of the weeks in April.

2. The second two numbers refer to the year. Of course, if the number is in the 90s, it refers to the last century – the 1990s. Most serial numbers on equipment still in use will show the years beginning with 0 or 1 for the 2000s and the 2010s.

How Old is My Carrier?

Here are a few examples we pulled from recent work. Can you tell the age of these ACs or furnaces based on the explanation just given?




Answers below.

Sometimes the tag gives a manufacture date – so it is really easy, as in this image:

As you can see, the Date of Manufacture, Oct 2006, matches the information from the serial number – the first two numbers “40” is the 40th week, which is in October. And the next two numbers, “06,” is the year, or 2006. 4006 = October 2006.

Tip on Carrier age: 9 or 10 characters in the serial number? It doesn’t matter. Carrier AC, furnace and heat pump units manufactured in the last 20+ years have 10 characters – numbers mostly and one or two letters. Older units use a 9-character alphanumeric (letters/numbers) serial number. Decoding both types is the same: The 2-digit week first followed by the 2-digit year.

Answers – How Old is My Carrier?

When were these Carrier products made?

0519E28045 = The 5th week of 2019, so February of 2019.

3608A17330 = The 36th week of 2006, so around September of 2008.

2111Q76606 = 21st week of 2011, so May of 2011.

As you can see, if you have the serial number, there’s no need for an online lookup to try to determine its age.

What Do the Other Characters Mean?

We’ve decoded the first 4 numbers of Carrier serial numbers for AC, heat pump and furnace models.

Letter: The fifth character is often a letter, and the letter refers to a Carrier manufacturing facility or an assembly area in a factory.

Numbers: The remaining numbers refer to the manufacturing sequence, which could be the exact number of that furnace model ever produced (not produced in that week).  

Older Carrier Serial Numbers

Do you have an “antique” Carrier AC or furnace?

Here are a few older serial number styles Carrier used – and how to determine the age of the equipment.

1960s – 7 Numbers

Example: 4257682

Determine the year: The first digit is the year, or 1964.

1=1961, 2=1962, etc.

No reference to the week is given.

1970s to 1980 – 9 Numbers

Example: 734494072

Determine the year: First two numbers, so 1973

Determine the week: Numbers 3 and 4, so week 44

Alternate 8-character Alphanumeric Serial Numbers

This system was used on a few types of equipment in the 70s and 80s.

Example: D749750B

Determine the month: The letter that begins the Carrier serial number specifies the month. January = A, February = B, March = C, April = D and so forth. This furnace was made in April.

Determine the year: The first two numbers refer to the year. This furnace was built in 1974.

Note: As in the serial numbers with 9 and 10 characters, the remaining numbers and letters in the older serial numbers refer to manufacturing sequences and the plant where the product was manufactured.

Can’t Find the Age of your Carrier?

The examples given above cover more than 95% of Carrier AC, heat pump and furnace models produced in the last 50 years.

If your unit’s serial number is something unusual, and there are a few out there, we recommend an online lookup – just type into the search box “Carrier serial number” and then whatever the number is. 

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree from Lone Star College and EPA & R-410A Certifications.

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