Goodman serial number lookup: age of a furnace, AC or heat pump

The serial number is on the rating plate: on the back of an outdoor unit, or on the inner wall of a furnace cabinet. A Goodman serial is ten digits. The first two are the year and the next two are the month.

Decode a Goodman serial number

Look for “Serial”, “Serial No.” or “S/N” on the rating plate. It is not the model number. What you type stays in your browser.

How to read a Goodman serial number

Built since the early 1990s

Year and month, first four digits

The first two digits are the year and the next two are the month.

Shape: ten digits with no letters. A few Amana serials have nine.

18year04month165082
Example: serial 1804165082 reads as April 2018.

Goodman’s service bulletin lists the example serial as built on April 11, 2018. One widely copied chart calls the third and fourth digits the week. Goodman’s warranty documents and the serial ranges in recall notices show that they are the month.

Where to find the serial number

On an air conditioner or heat pump the rating plate is on the back of the cabinet, a little above the refrigerant valves.

On a furnace or air handler the plate is on the inner wall of the cabinet. Open the furnace door to see it.

Installers often tape the label from the shipping carton, which repeats the serial, to the installation paperwork.

If the serial number does not decode

  • If the third and fourth digits are higher than 12, the serial is not in this layout.
  • When the installation date cannot be verified, Goodman counts warranty from the manufacture date plus three months, so the date in the serial is also the date the warranty runs from.
  • Janitrol, a brand Goodman built from 1982 to the mid-1990s, uses the same code.
  • Gas furnaces from the 1980s and 1990s print the year of the safety standard they were certified to, for example “Z21.47” followed by a year. The furnace was built in that year or a few years after it.
  • The manufacturer can confirm the date from the serial: Goodman registration, warranty or serial lookup.

What the age tells you

EquipmentTypical service life
Furnace15 to 22 years
Central air conditioner10 to 21 years
Heat pump15 to 16 years

What size is it?

The model number on the same rating plate gives the size: the tonnage of an air conditioner or heat pump, or the heating input of a furnace. Goodman model number tonnage shows where the digits sit and reads them for you.

About Goodman

Goodman Manufacturing was formed in 1975, bought Janitrol in 1982 and Amana’s heating and cooling business in 1997, and has belonged to Daikin of Japan since 2012. Goodman, Amana and Daikin ducted equipment is built on the same lines in Texas and shares one serial code.

Brands that share this serial system: Amana, Daikin.

Questions and answers

Which characters in a Goodman serial number show the date?

The first two digits are the year and the next two are the month. This applies to units built since the early 1990s.

Are the third and fourth digits of a Goodman serial the week or the month?

The month. Some charts say week, but Goodman’s warranty documents say month, and recall notices list serial prefixes that only make sense as months: air handlers recalled for November 2015 to October 2016 carry prefixes 1511, 1512 and 1601 to 1610.

Sources

Formats last checked against these sources on October 5, 2026. Found a serial that does not fit? Send a correction. How formats are verified: method and sources.