Have you ever looked at your furnace and wondered how old it is? For my clients I try to answer this question. All it requires is for you to know the brand and serial number of your furnace. Then it is as simple as going to this site and looking up the info. The home page of this site contains two symbols. One is for quick age HVAC - (Heat and A/C). The other is quick age Water Heater. Click on the one you are interested in, find your brand and then click on it. There are instructions there on how to read the serial number to determine the date of manufacture.
But where are the serial numbers you ask? The Water Heater serial numbers are located on the outside of the tank and should be easy to find. The Furnace Serial number is probably behind an access panel. The A/C or Heat Pump will have two serial numbers (one on the compressor (outside) and one on the evaporator coil (inside).)
Not all brands are included but for the majority of people this site will help you determine the age of your HVAC or Water Heater.