About this site and our method
Each filter size and date rule here comes from the maker's own page or PDF. We copy it as printed and show the date we read it.
Scope: air filter sizes and manufacture-date codes only; no repair, replacement or safety advice.
What rules do we follow?
- Makers' sources only. Each size and each date rule comes from the maker's own page or PDF. We do not copy from retailers, lookup sites or other compilations.
- As printed. We copy figures in the maker's units and format. Where we do arithmetic, we say so.
- Dated. Every source shows the date we read it. Every page shows a “Last updated” date.
- More than one date. If the maker's table gives more than one date for a code, we show each date.
- Manufacture date only. A date code is not an install date and says nothing about warranty status or the unit's condition. Ask a licensed professional about your equipment.
How do we keep figures current?
We save a copy of each source with a checksum on the day we read it.
Which makers are missing, and why?
- Carrier and Bryant: Carrier's FAQ explains where the serial plate is but not how to read the date.
- Trane: the Trane page we found covers light commercial units only, and parts of its year table look inconsistent.
- Nordic Pure and Filtrete sizes: the maker pages we read did not show an actual size.
How are corrections handled?
If a maker publishes a different figure, we update the page and the date.
Who runs this site, and how do I report an error?
Written and checked by the HVAC Label Guide team.
To report an error or ask a question, email [email protected].