Age of Heil unit Find an InterNACHI certified Illinois Home Inspector (and anywhere else in North America) Re: Age of Heil unit For Heil First four numbers of the serial number YYWW: For International Comfort the Letter indicates the month and the first two digits indicate the year. So according to Heil this was manufactured in the 6th wk of 2000. (But remember it may have set in a warehouse for a while before being installed. ) International Comfort Date is Nov of 2000. Regardless of which number you choose it is 2000. There is also a recall on Heils ...http://www.cpsc.gov/cpscpub/prerel/prhtml06/06011.html So the sellers are going to be really mad... too bad. Home Inspections for Springfield, Dayton, and surrounding OH areas. What is your HVAC procedure? 980 Questions/Answers to the NHIE.... what the Heil is a Heil unit? Need Assistance on A/C Unit Computers / Tips and Solutions Convert an Old Hard Drive into an External Unit