How to read Nordyne, Intertherm and Miller serial numbers

This covers Nordyne, Intertherm, Miller, Frigidaire, Maytag, Westinghouse, Broan, GrandAire, Philco, NuTone, Kelvinator, Tappan, Gibson, Mammoth. The serial number is on the data plate on the unit.

Brand on the labelSerial number

Reading it yourself

Twelve characters that start with two letters. The fourth and fifth characters are the year.
Example: GSD060700023 was made in 2006.

This is the date the unit was made. It was usually installed soon after, but it can be later. If a serial doesn’t fit any of these patterns, look on the label for a printed manufacture date.

Sources

Checked in October 2026.

Furnace Age, Energy Trust of Oregon
Frigidaire HVAC age, Building Intelligence Center

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