What is the difference between a windqw A/C and a split A/c/

I know I have two stage heat because of the aux. heat option. But how do I determine whether I have two stage cooling?

My air handler is located in my garage. Why can I hear water running when I'm standing by the air filter return? My drain pan and coils have been recently cleaned. Should I call someone out to look at it, it runs and cools fine. I don't want to have a leak in an unforseen place and I see nothing...

Hai iwant to know how to calculate the total building load and equipment seletion and pump selection(pump head)

Age of equipment, best you can tell... 10yrs Brand (Manufacturer)... nordyne.. intertherm Efficiency... see here Air conditioner... Package unit split system, (furnace inside A/C outside)... What does it do? Not do? It blows a little bit, but the air is like a vent not cool. W e...