Appearance of Exterior AC Unit
The general appearance of the exterior A/C unit doesn’t always tell you how old or in what condition the unit is really in.
When you walk around the home and see the A/C in the side or back yard does it look old and worn out, does is look weather worn, rusty, deteriorating? The first things you should look for before jumping to any conclusions is: How exposed is the unit? (does it have shade from trees? bushes? fence or blind? patio cover? no shade at all?) and: Is the unit on the south and/or west side of the home?
AC Components Protected
The appearance an exterior A/C unit can often be affected by sunlight and weather. While the critical components are protected inside the housing the housing itself can be taking a beating from the elements. This can make an exterior unit look suspiciously old and worn out to many realtors and LOTS of clients.
So how old is the A/C unit at the home your client is looking to put a contract on? On MOST units it is a simple matter of looking at the first 4 numbers of the serial number. But even that can be tricky because some manufacturers put the year in the first 2 numbers of the serial and some in the third and fourth numbers (i.e. 13405USU2E) and I have to tell you that some manufacturers hide it better than that. Whichever one of the ‘first 4 numbers’ format a manufacturer uses for the year keep in mind those other 2 numbers will be the month or week of production. The month or week a unit was manufactured is really not much use for us – so which 2 numbers are the real year of manufacture? .
Age Of AC Unit
If a serial number is: 13405USU2E it is safe to say that is wasn’t manufactured in 1940 or 2040 so it stands to reason that it is probably a 2013 model manufactured in the 40th week of the year. Trane & Payne
Same is true for this serial number: W291013412 it is probable that the manufacture date is 29th week of 2010. Rheem
But a little logic helps figure out the date whether the manufacturer uses a month and year or week and year date code: 9704011000 this unit could be a 1997 or a 2004 model BUT it can not be manufactured in the 97 month or 97 week of the year, so it is probably a 1997 model manufactured in the 4 week or 4th month of the year. Goodman
Then there are the companies that use a letter code for the date of manufacture. For example General Electric uses 2 letters coded at the beginning of their serial number for date of manufacture. We won’t even go into Guardian (in picture), York and Coleman that use the 2nd and 4th numbers to indicate the year – and the 3rd number (letter) to indicate the month?!?!? Hu? Why?
AC Age Cheat Sheet
So the easiest and surest way to determine the age of an AC unit is to use a cheat sheet. There is such a cheat sheet online at BuildingCenter.org . They have lots of good info on the age of HVAC units and WATER HEATERS, as well as some good general building industry information.