How old is my Rheem furnace or AC?

Rheem and Ruud heating and cooling equipment encodes the week and year right after a plant letter. On older units that letter sits in the middle of a long serial; on newer ones it's the first character.

The same rules apply to Ruud furnace, AC and heat pumps.

By equipment type

• Rheem furnace age

  Typical life: 15–20 years

• Rheem air conditioner age

  Typical life: 10–15 years

• Rheem heat pump age

  Typical life: 10–15 years

• Rheem water heater age

  Typical life: 8–12 years

• Rheem tankless water heater age

  Typical life: 15–20 years

Where to find the serial number

Furnaces: the rating plate is inside the burner or blower compartment door.

Outdoor units: the plate is on the side of the cabinet. Many Rheem plates also print MFD. with the month and year.

Questions

What does 5076 G0994 3554 mean?

The four digits after the plant letter G are 0994: the 9th week of 1994. That unit's plate reads MFD. 03/94.

Is a Rheem water heater decoded the same way?

No. Rheem water heaters have their own format; see our Rheem water heater page.

Same serial format

Ruud

Sources

• CPSC 1999: Rheem electric furnace / air handler recall ('four digits following the letter M' = week + year)
• CPSC 2009: Rheem oil-fired furnace recall (date code after the middle letter)
• How To Look At A House: Rheem air conditioner or furnace age (plate-confirmed examples)
• Building-Intelligence Center: Rheem HVAC age
• Rheem Technical Service Bulletin 1207: How to locate and read Rheem/Ruud/Richmond serial numbers
• CPSC 2016: Rheem water heater recall (serial date codes)
• Rheem: How to locate and read your water heating serial numbers

Rules last reviewed 2026-09-28. 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.