About
Serial Number Age answers one question: how old is this furnace, air conditioner, heat pump or water heater? Homeowners ask it when something breaks, buyers ask it during a home purchase, and inspectors ask it on every job.
The answer is usually hidden in the serial number, but every manufacturer uses its own code, some have changed it several times, and the guides online often contradict each other. We wrote each code as a set of rules, tested them against serial numbers with known dates, and built a decoder that shows its working, including when a serial could mean two different dates.
We are independent and not affiliated with any manufacturer. Brand names are used only to say which equipment a code applies to.