The short answer
On most Goodman furnaces, air conditioners and heat pumps in Northern Virginia, the first four digits of the serial number are the year and month the unit was built. A serial starting 1806 means June 2018. That’s Goodman’s own rule, from its warranty paperwork. Put the age next to the repair price and you’ll know whether to fix it or replace it.
Where the serial number is
It’s on the rating plate, a sticker or metal plate with the model and serial numbers. Goodman’s manuals name the plate but not where it sits, so this is where our techs find it:
- Furnace: inside the front door, on the cabinet wall. Some print a copy on the outside of the door. Don’t take a panel off to find it: the door switch cuts the power, and some doors hide live wiring and the burners.
- Air conditioner or heat pump: on the side of the outdoor unit, a metal or foil plate near the corner where the power line comes in.
Take a photo of the whole plate. The model number on it matters as much as the serial.
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Reading the date
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| Serial starts with | Built | Age this winter |
|---|---|---|
| 0611 | November 2006 | 20 years |
| 1104 | April 2011 | 15 years |
| 1806 | June 2018 | 8 years |
| 2203 | March 2022 | 4 years |
The rule is in Goodman’s furnace warranty, whose example is 1306 for June 2013, and Daikin’s furnace warranty says the same; Daikin owns Goodman and Amana. Goodman’s extended warranty application says it holds “for most products,” so if the third and fourth digits come to more than 12, they aren’t the month and the unit uses another format. Our equipment age decoder reads a photo of the plate, or a tech can date it on the visit.
What the date means for your warranty
Goodman’s furnace warranty runs from the day the furnace was installed. If that date can’t be shown, it starts three months after the manufacture date in the serial number, per the same warranty. Registering it online within 60 days of the install changes the terms too. So keep the install invoice; it and the registration have the terms for your unit.
How old is too old?
Goodman doesn’t publish a service life. These are the ranges our techs see in Northern Virginia, and the ones our age pages use. A heat pump runs summer and winter, so it wears fastest.
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| Equipment | Typical life here | What a new one costs |
|---|---|---|
| Gas furnace | 15 to 20 years | $4,285 to $14,040. From about $71 a month at 0% APR for 60 months, the whole price financed, on approved credit. |
| Air conditioner | 12 to 15 years | $5,942 to $14,450. From about $99 a month at 0% APR for 60 months, the whole price financed, on approved credit. |
| Heat pump | 10 to 15 years | $8,499 to $21,650. From about $142 a month at 0% APR for 60 months, the whole price financed, on approved credit. |
Age alone isn’t a reason to replace a system that runs well. The call comes when a big repair lands on an old unit: a compressor on a 13 year old heat pump, or a heat exchanger on an 18 year old furnace. The tech gives you the repair price and the replacement price side by side, in writing, so you choose.
The model number tells you more
On Goodman’s newest outdoor units, the ones on R-32 refrigerant, the model number spells out what you have. It starts with G for Goodman, then L for a split system on R-32, then Z for a heat pump or X for an air conditioner, then S for single-stage or T for two-stage. Two digits later in the number give the size: 18 is 1.5 tons, 36 is 3 tons, and 60 is 5 tons. That’s from Goodman’s R-32 model number guide. Older models use other patterns, and our refrigerant guide covers why the newer refrigerants matter if you’re replacing.
For other brands, our age pages decode the serial for you: how old is my furnace, my air conditioner and my heat pump. If your Goodman is showing a code, start with our Goodman furnace codes chart or the Goodman heat pump and AC codes.
More Goodman and Amana, one problem at a time: pressure switch: 3 flashes or EE2; limit switch: 4 flashes or EE3; lockout and weak flame: 1 flash, EE0, EE6; solid red light, no light or rapid flashing; rollout switch: 6 flashes or E11; Goodman heat pump and AC codes; flame sensor: 7 flashes or EE6; display codes: 1dL, 9H, F02; how to reset a Goodman furnace; inducer motor noises and codes; troubleshooting by symptom; Amana furnace codes; a Goodman heat pump that won’t heat; a Goodman furnace that keeps shutting off; a Goodman furnace blowing cold air. Other brands are in our error codes and warning lights guide.
Get it fixed
Call (703) 997-9757 and we’ll get a tech out to look at your Goodman and tell you whether it’s worth fixing. We answer day or night. Rather book online? Pick a time here and a box of warm cookies comes with the visit. A repair visit starts with our $99 diagnostic, and you get the price in writing before any work starts. Already have a quote? We’ll give you a free second opinion. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
How do I tell how old my Goodman furnace is?
Find the serial number on the rating plate, usually inside the front door. The first four digits are the year and month it was built: 1806 means June 2018.
What does a Goodman serial number starting with 1806 mean?
Built in June 2018. Digits one and two are the year, three and four the month, per Goodman’s warranty. That unit is 8 years old this winter.
Do Amana serial numbers work the same way?
Often. Goodman and Amana are the same company, and many Amana serials start with the year and month too. Older ones can use other formats, so if the date doesn’t make sense, send us a photo of the plate or use our equipment age decoder.
Is it worth repairing a 15 year old Goodman furnace?
For a small repair, usually yes: the range our techs see here is 15 to 20 years. For a big one, or a third repair in a couple of years, compare it with a new furnace at $4,285 to $14,040. From about $71 a month at 0% APR for 60 months, the whole price financed, on approved credit.
