About
A free, independent tool for one everyday question: how old is the equipment in my house?
Why this site exists
The age of a water heater, furnace or air conditioner drives a lot of decisions: whether a repair is worth it, how much to budget for next year, what to ask for in a home sale, whether the warranty might still apply. The answer is printed on almost every unit, but it's hidden in a serial number that only makes sense if you know the manufacturer's code.
Those codes are scattered across manufacturer bulletins, distributor sheets, inspector training notes and forum threads, and they differ by brand and by decade. MfgDate gathers them into one tool that does the decoding for you and explains what the result means.
Who runs it
MfgDate is run by MfgDate. We're not a manufacturer, a dealer or a contractor, and no brand pays to be listed or ranked. You can reach us any time through the contact page.
How we build the decoders
Each decoder starts from the manufacturer's own documentation where it exists: serial number nomenclature bulletins, product data sheets, installation manuals and warranty lookup guidance. Where a manufacturer doesn't publish its format, we work from distributor and inspector references and confirm the rule against real data plates whose dates we know.
Every rule is covered by automated tests that run before each update goes live. A decoder is marked verified only once it correctly dates a set of real serials; until then it's labeled as an estimate still being checked. The full list, with the status of each brand, is on How Our Decoders Work.
How you can help
If the tool gets your unit wrong, or doesn't recognize it, please tell us. A serial plus the date printed on the label (or the install date) is the single most useful thing anyone can send, and every correction makes the tool more accurate for the next person.
What we don't do
- We don't store the serial numbers you type into the lookup. Decoding happens in your browser.
- We don't give repair instructions for gas, electrical or refrigerant work. Those belong with a licensed pro.
- We don't claim to speak for any manufacturer. See our disclaimer and trademark notice.