Appliance Age Decoder turns the serial number on a water heater, furnace, air conditioner or heat pump into a build date, an age, and a plain answer on whether to start planning a replacement.
Each brand's rule is written down once, in one table, and every page is generated from that table. A rule goes live only after it has been checked against published sources, and each brand page shows how many sources agreed. When a serial could mean more than one year, the decoder shows every possible date instead of picking one.
The verdict compares the age with a typical lifespan range for that kind of equipment. It is a guide, not an inspection. Rust, leaks, noise, repair history and water quality matter as much as the calendar.
The site shows ads, earns a commission on some Amazon links, and may be paid a fee when you ask for quotes from an installer. None of that changes the date or the verdict the decoder gives you.
Tell us the brand, the serial number and the date printed on the label, and we will check the rule. Write to [email protected].