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Carrier family

How old is my Day & Night heat pump?

Enter the serial number from the label. The date comes from Day & Night'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 Day & Night heat pump serial number

  • Week + year, plant letter, sequence (1988 onward)

    Example: 4006A17330 (Carrier) was made in October 2006. In Carrier, Bryant and Payne serials the first two digits are the week (40) and the next two are the year (2006). The letter after them is the factory.

Not decoded yet: Pre-1988 Carrier, Bryant and Payne formats (month letters, week + year letter, all-numeric) are not decoded because sources disagree.

Where to find the serial number

The rating plate is on the outdoor unit, usually on the side or back of the cabinet near the electrical disconnect.

The indoor air handler has its own plate and its own serial number, so check which unit you're decoding.

How long does a heat pump last?

A typical heat pump lasts about 10–15 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 InterNACHI: standard estimated life expectancy chart, Carrier: how long do heat pumps last? and Lennox: how long do heat pumps last?.

Day & Night heat pump recalls

No Day & Night heat pump 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 Day & Night heat pump is?
Find the serial number on the rating plate and enter it above. Day & Night heat pumps use the Carrier family serial format, which includes the manufacture date. For example, 4006A17330 was made in October 2006: In Carrier, Bryant and Payne serials the first two digits are the week (40) and the next two are the year (2006). The letter after them is the factory.
Where is the serial number on a Day & Night heat pump?
The rating plate is on the outdoor unit, usually on the side or back of the cabinet near the electrical disconnect. The indoor air handler has its own plate and its own serial number, so check which unit you're decoding.
How long does a heat pump usually last?
A typical service life is about 10–15 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 Carrier, Bryant and Payne heat pumps use the same serial format?
Yes. Day & Night, Carrier, Bryant and Payne use the same serial-number conventions (Carrier family), so the same decoding rules apply.
How reliable is the result?
The Carrier 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: Carrier heat pump, Bryant heat pump, Payne heat pump

Other Day & Night equipment: furnace, air conditioner

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.