Heat Pumps and Electric Heating - I Need a Primer for HP Multi-Stage

Ok, I know I have a heat pump that has emergency heat. It is 14 years old and is original to the house. I just don't know anything else about it. Here is where my problem is. How do I figure out if I have a multi-stage unit or not? BTW, what is a multi-stage unit in laymens terms? I am looking at the Hunter 44760 (http://www.hunterfan.com/prodSum.php?pid=20&pType=thermo&sType=4) . I want auto-switch but I am not sure if that is possible with my system. Thanks for any info.

Aux heat strips set up on multi stage simply means the heat coils are setup to come on in stages instead of all kicking in at once, which would be single stage. Heat pumps sometimes just need a small boost to keep the set temp, it does not make good economic sense to throw 15kw (or whatever heat capacity you have) at it all at once, kinda wasteful. I assume that all your unit info has long ago faded into nonreadable gibberish. Best bet is to Lockout Tagout all power sources to your unit, pull the unit panel and simply see how the coils are wired up or have a tech come out and check it out for you.