How old is my furnace, water heater, or AC?
Type the serial number from the data plate. The decoder reads the manufacture date for 9 brands and shows where that age sits on a typical lifespan.
Free, no account. Every format comes from the manufacturer's own date code and is tested against real serial numbers before it goes live.
Example: Rheem water heater, serial Q111516703
Made Mid March 2015
11 years, 7 months old
The serial reads as week 11 of 2015 (About 2013 to today format). Made, not installed: most units go in within a year of the factory date.
In the replacement window
A tank water heater (gas or electric) typically lasts 8 to 12 years, and this one is in that range. It may keep going, but this is the age to budget for a replacement rather than wait for it to fail.
Decoders by brand
One page per brand, with the date code explained, real examples, and where to find the data plate. Brands that share a bigger maker's code are listed with it.
Water heaters
AC and heat pumps
Where the serial number is
Look for the rating plate, a metal or foil label with the model and serial numbers. Use the serial, not the model number: only the serial carries the date.
Water heater
On a tank, the rating label is on the side near the top or just above the gas valve or the electrical cover, among the warning labels.
AC or heat pump
On the outdoor unit, usually a metal or foil plate on a side or back panel near where the refrigerant lines go in.
What the age means
Typical service life by equipment type, from inspector and builder life-expectancy references. Water quality, maintenance and climate move the real number.
| Tank water heater (gas or electric) | 8 to 12 years |
| Tankless water heater | 15 to 20 years |
| Gas furnace | 15 to 20 years |
| Central air conditioner | 10 to 15 years |
| Heat pump (air-source, ducted) | 10 to 15 years |
| Ductless mini-split heat pump | 15 to 20 years |
| Cast-iron (non-condensing) boiler | 20 to 30 years |
| Condensing (high-efficiency, often wall-hung) boiler | 10 to 15 years |
How the decoder is checked
Each brand's rule links the manufacturer page it came from and is tested against real serial numbers whose dates we confirmed independently, from the label, the manufacturer, or two sources that agree, before it goes live. A serial we can't read gets "format not recognized", never a guess. See the methodology.
A serial that didn't decode, or decoded wrong?
Send it with the brand and equipment type. Every submission is checked by hand and, once resolved, becomes a test the decoder must pass.
Email the serial number, the brand, and whether it's a water heater, furnace, AC or boiler to support@factorydate.com.
If the label prints a manufacture date, include it: that's what lets us confirm a new format. A photo of the plate helps too.