Package Unit  A self contained system that has the air handler and condenser in the same unit. This unit may be placed outside, in the attic or on the roof. This is normally connected to a duct  system through the home’s foundation.

Air Conditioner  Device used to control temperature, humidity, cleanliness and movement of air in a confined space.

Heat Pump  A heating and air conditioning unit that heats or cools by moving heat. When you run your air conditioner, your outdoor unit will be blowing hot air [removing heat from your home and sending it outside]. When you run your heat, it reverses the flow and remove heat from the atmosphere outside and blow it inside. In southern climates, the heat pump is generally more energy efficient.