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Rinnai tankless

How old is my Rinnai tankless water heater?

Enter the serial number from the label. The date comes from Rinnai'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 Rinnai tankless water heater serial number

Rinnai prints the manufacture date at the start of the serial. Units built since mid-2010 use a year letter and a month letter (like BH.AB-000123). Older units use numbers: year, a period, then month (like 03.06-001000).

  • Year letter + month letter (mid-2010 onward)

    Example: BH.AB-000123 (Rinnai) was made in August 2010. Rinnai's first letter is the year ("B" = 2010) and the second is the month ("H" = August). The next two letters are the factory and product type.

  • Year.month numeric (before mid-2010)

    Example: 03.06-001000 (Rinnai) was made in June 2003. In Rinnai's older format (printed like "03.06-001000"), the first two digits are the year (2003) and the two after the period are the month (June).

Not decoded yet: 8–9 digit numeric serials (about 1999–2008) are documented only by industry sources and aren't decoded yet.

Where to find the serial number

The rating label is on the side of the unit's cabinet. Some models also show it behind the front cover.

The rating plate is on the side or bottom of the unit's cover. On some models you'll find it inside the front cover.

The serial begins with two letters and a period (newer units) or two digits and a period (older units).

Rinnai tankless water heater model numbers

If the brand name isn't visible on the label, the model number can help. Model numbers like these follow Rinnai's published nomenclature:

How long does a tankless water heater last?

A typical tankless water heater 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. The U.S. Department of Energy estimates an average of about 20 years.

Range from A. O. Smith: how long do water heaters last? and U.S. DOE, gas-fired instantaneous water heater standards, 89 FR 105188 (2024).

Rinnai tankless water heater recalls

No Rinnai tankless water heater recalls were found in U.S. Consumer Product Safety Commission data when this page was checked (2026-09-29). A decoded result checks your model number live.

Questions

How can I tell how old my Rinnai tankless water heater is?
Find the serial number on the rating plate and enter it above. Rinnai tankless water heaters use the Rinnai tankless serial format, which includes the manufacture date. For example, BH.AB-000123 was made in August 2010: Rinnai's first letter is the year ("B" = 2010) and the second is the month ("H" = August). The next two letters are the factory and product type.
Where is the serial number on a Rinnai tankless water heater?
The rating label is on the side of the unit's cabinet. Some models also show it behind the front cover.
How long does a tankless water heater 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.
How reliable is the result?
The Rinnai tankless 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.
What does BH.AB-000123 mean?
B is 2010 and H is August, so the unit was made in August 2010. The next two letters are the factory and product type.
Which letters does Rinnai skip?
Rinnai's year table skips I, O, Q, U and V. Some unofficial charts list O for 2022, but Rinnai's own table uses P.

Sources

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.