How old is my Heil furnace?

Serial number age decoder for Heil furnaces: 2 format eras, the decode rule in plain English, transcribed tables, and the official lookup.

Serial number decoder for Heil furnace

Serial no.

Type the serial from the data plate, not the model number. Nothing is sent anywhere; the tables are in this page.

Format example: 4006A17330

Heil furnace serial numbers in the 1980 to present format encode the year as digits 3-4 (2-digit year; century by context, 1980+) and the week as digits 1-2 (01-53) (source: building-center.org).
Example: serial 4006A17330 decodes to week 40 of 2006.
Heil furnace serial numbers in the before 1979 format encode the year as digit 1 = last digit of year; decade unknown (297448 = 1952, 1962 or 1972) (source: building-center.org).
Example: serial 297448 decodes to 1952 or 1962 or 1972.
The before 1979 format is ambiguous: 6-digit numeric; decade must come from ANSI date, model nomenclature, or purchase records.
Heil's official lookup at heil-hvac.com returns warranty / registration lookup.

Format eras

1980 to present VERIFIED
####A#####digits 3-4 (2-digit year; century by context, 1980+)
before 1979 VERIFIED
######digit 1 = last digit of year; decade unknown (297448 = 1952, 1962 or 1972)

How to read the serial

1980 to present formatVERIFIED

Shape ####A##### · example 4006A17330 · confidence high

Year: digits 3-4 (2-digit year; century by context, 1980+)
Week or month: week = digits 1-2 (01-53)
Plant: letter at position 5 (plant/line code; table not published)

Example: serial 4006A17330 decodes to week 40 of 2006.

Trap: Same 4-digit-letter-5-digit shape as Lennox style 1 (Lennox = plant,plant,YY,month-letter). Two-digit year needs century disambiguation (e.g. 06 = 2006 vs 1986); use ANSI/date on plate.

Listed under Carrier in the source; Heil is named in that format's family.

before 1979 formatVERIFIED

Shape ###### · example 297448 · confidence low

Year: digit 1 = last digit of year; decade unknown (297448 = 1952, 1962 or 1972)

Example: serial 297448 decodes to 1952 or 1962 or 1972.

Trap: 6-digit numeric; decade must come from ANSI date, model nomenclature, or purchase records.

Where the data plate is on a furnace

Inside the furnace: remove the upper (burner) access door and look on the inside of the door, on the blower compartment wall, or on a sticker facing you at the burner deck.

General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.

For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Furnace at 15 to 25 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.

Official lookup: the authority

Open the official Heil lookup takes serial number; returns warranty / registration lookup; URL verified live

This site is a reference built from published tables. The manufacturer's own lookup wins whenever the two disagree.

What we could not confirm

ICP brand (icpusa.com/en/us/our-brands). Styles: E072514528 (ICP L-YY-WW), H55116328 (1980s H+Y+WW), H55120465 (recall re-serial), 297448 (pre-1980 6-digit). Registration page 200, no serial-lookup text.