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Johnson Controls / York family

How old is my York furnace?

Enter the serial number from the label. The date comes from York's documented serial rules, not a guess.

Look for “Serial No.” or “S/N” on the label. Spaces and dashes are fine.

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How to read a York furnace serial number

York serials changed in October 2004. Newer ones start with a plant letter, the year’s third digit, a month letter and the year’s last digit, so W1H6… is August 2016. Older ones start with four letters for the plant, month, year and type of unit. Those year letters repeat every 21 years, so for older units we show both possible dates.

  • Plant letter + year digit + month letter + year digit (October 2004 onward)

    Example: N0L4123456 (York) was made in October 2004. Since October 2004, York-family serials start with a plant letter, then the year's third digit, a month letter and the year's last digit: "0" and "4" make 2004, and "L" is October. The month letters skip I and J.

  • Plant + month letter + year letter + unit-type letter (1971 to October 2004)

    Example: WFKM003055 (York) was made in June 2001 or June 1980. Before October 2004, York serials start with four letters: the plant, the month, the year and the type of unit. "F" is June. Year letters A to N repeat every 21 years, so "K" means 1980 or 2001.

Not decoded yet: Coleman, Evcon and Luxaire all-number serials, Luxaire two-letter serials, pre-2004 York serials with year letter P, and geothermal, ductless and commercial units.

Where to find the serial number

Turn the furnace off at its switch, then remove the upper access door (the burner or blower compartment). The rating plate is on the inside wall of the cabinet or on the back of the door.

The plate lists the model number and serial number; many newer plates also print a date of manufacture.

How long does a furnace last?

A typical furnace lasts about 15–20 years. That's a general estimate: maintenance, usage, climate and installation all matter, and age alone doesn't tell you a unit's condition.

Range from NAHB / Bank of America, Study of Life Expectancy of Home Components (2007, archived copy), Carrier: how long does a furnace last? and Lennox: how long does a furnace last?.

York furnace recalls

From the U.S. Consumer Product Safety Commission, checked 2026-09-29. A decoded result checks your model number against recalls live.

Questions

What does WFKM mean at the start of my York serial?
W is the Wichita plant, F is June and K is the year letter for 1980 or 2001. York’s own 2001 safety bulletin says units with the WFKM and WGKM prefixes were produced in Wichita in May, June and July 2001.
Why does my older York serial show two dates?
Before October 2004, the year letters A to N were reused every 21 years, so F can mean 1976 or 1997. Nothing in the serial tells them apart, so we show both. The rating plate or installation paperwork may settle it.
Can you date a Coleman or Evcon serial that’s all numbers?
Not yet. Industry references describe those formats, but we’ve found only one officially dated example, so they stay undecoded. Coleman, Luxaire and Evcon units made since October 2004 use the same format as York and are decoded.
How can I tell how old my York furnace is?
Find the serial number on the rating plate and enter it above. York furnaces use the Johnson Controls / York family serial format, which includes the manufacture date. For example, N0L4123456 was made in October 2004: Since October 2004, York-family serials start with a plant letter, then the year's third digit, a month letter and the year's last digit: "0" and "4" make 2004, and "L" is October. The month letters skip I and J.
Where is the serial number on a York furnace?
Turn the furnace off at its switch, then remove the upper access door (the burner or blower compartment). The rating plate is on the inside wall of the cabinet or on the back of the door. The plate lists the model number and serial number; many newer plates also print a date of manufacture.
How long does a furnace usually last?
A typical service life is about 15–20 years. That's a general estimate: maintenance, usage, climate and installation all matter, and age alone doesn't tell you a unit's condition.
Do Coleman, Luxaire, Fraser-Johnston and Evcon furnaces use the same serial format?
Yes. York, Coleman, Luxaire, Fraser-Johnston and Evcon use the same serial-number conventions (Johnson Controls / York family), so the same decoding rules apply.
How reliable is the result?
The Johnson Controls / York family rules come from documented sources, but they're in Beta while we check more real-world examples, so results are capped at medium confidence. If a serial doesn't match a documented format, we say so instead of guessing.

Same serial format: Coleman furnace, Luxaire furnace, Fraser-Johnston furnace, Evcon furnace

Other York equipment: air conditioner, heat pump

Sources

Rules last reviewed 2026-09-29. These rules are in Beta while we verify more real-world examples, so results are capped at medium confidence.

Manufacture dates are decoded from manufacturer serial-number conventions and available documentation. Serial formats can change. Verify critical equipment information with the manufacturer when necessary.