Every effort is undertaken to offer you correct and concise information to assist you in determining the age or manufacture date of HVAC equipment. Anytime anyone is dealing with numbers and letters in determining data, mistakes and misinterpretation are bound to happen. For this reason if you find during your research that we may have erred please contact us. In addition perhaps you have come across a brand, model or serial number format that we have not addressed. Email us information or pictures of data/nomenclature plates of the unit and we will attempt to assist you in your determinations. Email
This page was last updated: 26 July 2009
Grandaire
Serial Number format: GS3991251776
(This serial number is from an actual Grandaire A/C Unit).
Using the fourth and fifth digits of the serial number GS3991251776 you will find the year of manufacture. This unit was manufactured in 1999.
Year of manufacture: GS3991251776