HVAC Code Lookup

How old is my HVAC system?

Pick your brand, type the serial number off the rating plate, and get the month and year it was built. 13 brands decoded, each rule traced to a published reference. When a serial genuinely cannot pin one year, we show every year it could be instead of guessing.

The serial number is on the metal rating plate. On a furnace it is usually inside the front door on the side wall; on an outdoor AC or heat pump it is on the back or side of the cabinet, near the refrigerant lines.

Type the Amana serial exactly as printed. Spaces, dashes and lowercase are all fine.

Look up your brand

Each brand page explains that brand's serial formats and where to find the plate.

Amana

1 serial format

American Standard

3 serial formats

Bryant

2 serial formats

Carrier

2 serial formats

Coleman

2 serial formats

Daikin

Date printed on the plate

Fujitsu

Date printed on the plate

Goodman

1 serial format

Lennox

1 serial format

LG

1 serial format

Mitsubishi Electric

Date printed on the plate

Payne

2 serial formats

Rheem

3 serial formats

Ruud

3 serial formats

Trane

3 serial formats

York

2 serial formats

Find the rating plate

On a furnace, open the front door and look at the side wall inside. On an outdoor AC or heat pump, it is a metal or foil plate on the back or side of the cabinet. Mini-splits carry it on the outdoor unit and on the right side of the indoor head.

Serial, not model

The model number describes what the unit is; only the serial carries the date. They sit next to each other and get mixed up constantly. If the lookup says it does not recognise your entry, this is the first thing to check.

Age is not a verdict

Most systems run 15 to 20 years. An older unit that still heats and cools well does not need replacing because a website said so. Age matters most when you are weighing a big repair bill against a new system.

Brands with no serial date code

Daikin, Fujitsu, Mitsubishi Electric do not publish a serial-number date code, and the decoders that claim to read one contradict each other. We do not guess on these. Their rating plates print an explicit manufacture date instead, usually labelled MFG DATE or DATE OF MFR.

Where these rules come from

Worth being straight about this, because it differs from the rest of this site. Our fault-code pages quote manufacturer service manuals. Serial date codes are not something manufacturers publish, so these rules come from long-standing industry references instead, and we only ship a rule when the references agree. Where they conflict, such as Trane's pre-2002 letter years, we give the era and say why rather than pick a side.

Got an error code too?

Age tells you where a unit is in its life. The fault code tells you what is actually wrong right now. Look yours up by brand: