Furnaces, AC and heat pumps

How old is my Carrier furnace, AC or heat pump?

Carrier, Bryant and Payne share a serial format: week and year in the first four digits, then a plant letter. A Carrier from 1985 to today decodes the same way. Nine-digit all-number serials from the 1980s put the year first.

How to read a Carrier serial number

Week and year, then a letter (mid-1980s to today)

The first two digits are the week and the next two are the year. The letter in the fifth spot is a plant code.

0519E28045 reads as week 5 of 2019.

Two sources agree Building Intelligence Center, PickHVAC, Energy Trust of Oregon furnace chart, McGarry and Madsen Home Inspection

Nine digits, year and month (1980s)

On nine-digit all-number serials from the 1980s the first two digits are the year and the next two are the month.

850304091 reads as March 1985.

Two sources agree Building Intelligence Center, PickHVAC

Where to find the serial number

Furnace: inside the front panel or on the side of the cabinet.
AC, heat pump or mini-split: the plate on the outdoor unit, usually near the line connections.
Use the line marked Serial No. or S/N, not the model number. If the plate prints a manufacture date, use that.

How long should it last?

Typical life of a furnace: 15 to 20 years

A gas furnace usually lasts 15 to 20 years. Well-maintained units in mild climates reach 25; units that run hard with dirty filters fail sooner.

How long does a furnace last? · Should I replace my furnace? · HVAC.com, Lennox, InterNACHI (15-25)

Typical life of a central air conditioner: 12 to 15 years

A central AC condenser usually lasts 12 to 15 years. In hot climates where it runs most of the year, 10 is more typical; in the north, 20 is possible.

How long does a central air conditioner last? · Should I replace my air conditioner? · Bryant, Lennox, InterNACHI (7-15)

Typical life of a heat pump: 10 to 15 years

An air-source heat pump usually lasts 10 to 15 years. It runs in both seasons, so it logs more hours than a furnace or an AC alone.

How long does a heat pump last? · Should I replace my furnace? · Trane, Lennox, Bryant, InterNACHI

Should I replace it?

Should I replace my furnace? · Should I replace my air conditioner?

More Carrier pages

Carrier furnace age · Carrier central air conditioner age · Carrier heat pump age

Parts that help it last

Furnace filters Check the size printed on the old filter and buy the same. A clogged filter is the most common cause of avoidable furnace trouble.
Leak alarm Useful near a high-efficiency furnace or an AC coil, where condensate drains can clog.

Check your model and size before you buy. Amazon links are affiliate links: as an Amazon Associate I earn from qualifying purchases.

Keep a record of your home

The age you just looked up is the kind of fact that gets lost. A written record of serial numbers, install dates, repairs and who did the work saves the next owner, inspector or insurer from guessing.

Keep This With the House

A lifetime logbook for the house, organized by system, with room for serial numbers, install dates, repairs and contractors. It stays with the house for the next owner.

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The House Has Old Pipes

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The House Is Fifty Years Old

A buyer's guide to older homes: wiring, pipes, lead, asbestos, insurance refusals and what the repairs actually cost.