How old is my Goodman furnace or AC?

By Dana Whitlock. Updated October 2026. Official format.

A Goodman serial that starts 1811 was built in November 2018. On a Goodman furnace, air conditioner or heat pump, the first two digits are the year and the next two are the month, so 0606 means June 2006.

Goodman's own warranty certificates say the first four digits of the serial (YYMM) indicate the manufacture date, so this is an Official format. The build date isn't the install date, though. Most units sit in a warehouse or on a supply house shelf for a few months first, which means your system has been running a little less time than the serial suggests.

Where to find the label on a Goodman furnace

Goodman condensers and heat pumps carry the rating plate on the outside of the cabinet, usually on the side facing the house or near the service valves. On a furnace or air handler, the label sits inside the access door, as the CPSC recall notices for Goodman furnaces and air handlers describe. Turn the furnace off at the thermostat and at its service switch before you lift the blower door. Use a flashlight and your phone camera instead of leaning into the cabinet. If a panel is held on with screws, leave it in place. Anything behind a screwed panel is a job for a licensed HVAC technician. The plate lists the model number, the serial number, the refrigerant type and the electrical rating.

How to read the code

A standard Goodman serial is ten digits, all numbers, with no letters. Split it as YY MM and then a six-digit production sequence. The year comes first: 96 means 1996, 07 means 2007, 21 means 2021. The month is a plain number from 01 to 12. If digits three and four come out as 00 or anything above 12, you are not looking at this format, so check that you copied the serial and not the model number. The last six digits only count units off the line and say nothing about age.

Real serials in this code

When the format changed

Goodman has used the YYMM scheme for decades, and published serials from real units go back at least to 1996, such as the condenser 9601095027 that inspectors read as January 1996. Two edge cases matter. First, evaporator coils: a 2024 CPSC recall notice explains that some coils built in 2019 carry a 2018 serial prefix, so a coil's prefix can run ahead of or behind its real build month. Second, older packaged terminal units (the through-the-wall kind used in hotels and apartments) sometimes use a different letter-based serial that this rule does not read. If the plate shows a printed date, trust it over any decoding. Goodman's warranty lookup also returns the unit's details once you enter the serial.

Who makes Goodman

Goodman is part of Daikin Comfort Technologies Manufacturing, which the CPSC lists as 'formerly Goodman Manufacturing Company' of Houston, Texas. Amana-brand and Daikin-brand ducted furnaces, air conditioners and heat pumps come from the same company and use the same YYMM serial, so the same reading works on all three. Goodman equipment is sold through independent heating and cooling dealers across the US rather than in big-box stores.

How sure is this?

Official format. Goodman publishes how its serial numbers encode the date. We tested the goodman daikin rules against 17 serials, 6 of them with a date known from a recall notice, a printed label date or the maker. None decoded to a wrong year; codes whose year mark repeats show every possible reading. Always confirm with Goodman's serial lookup before you spend money on the answer.

Quick notes

• Photograph the whole rating plate along with the serial, so a contractor can confirm the model and refrigerant later.
• If your outdoor unit and furnace show different years, the system was probably replaced in stages. Date each piece on its own.
• A Goodman unit with R-22 printed on the plate is usually from before 2010. EPA rules allow new R-22 only for equipment made before January 1, 2010.
• Run the serial through Goodman's warranty lookup to see whether the unit was registered and what coverage still applies.
• A middle pair of 00 or anything above 12 means you copied the model number. Go back for the all-numeric field.