What’s the difference?
A heating and air conditioning system is comprised of several subsystems: refrigeration, ventilation, gas, condensate drains, electrical controls, etc. These systems can be all within one cabinet/package or split into two separate cabinets. Hence the names package and split. The subsystem most affected is refrigeration.
Just a quick overview of the refrigeration system:
In a packaged system, the entire Refrigeration Subsystem will be contained in one cabinet commonly located outside the home (inside if geothermal). In a split system, the Refrigeration Subsystem will be in two cabinets. The two components above the dividing line in Figure 1 will be in one cabinet. The two components below will be in another. The two above will be in the air handler or near the furnace located somewhere inside or under the home. The two components below the dividing line will be in the condenser located outside the home. In a split system, the condenser and compressor will be connected to the evaporator by an extended suction and liquid line. These lines will be made of copper. They will run through your walls, attic, basement, or crawlspace. The liquid line will be insulated with a foam rubber sleeve. This line connecting the two is called the lineset.
Why does it matter?
The primary contributor to cost in any air conditioning installation is the equipment. When it comes to package and split, it’s similar to the difference between buying a truck or buying a car and a trailer. With a truck, you might sacrifice passenger space and comfort for towing power and loading capacity. With a car and trailer, you have some more options but where do you park the trailer? At the lower end of efficiency and size, a package unit will cost more than a split system. As size and efficiency go up, split systems will top out at much higher prices than a package unit.
The second major cost difference between package and split is the installation itself. Generally, the installation of a split system is more tedious and longer than a package unit. The most significant difficulty of a package unit is the sheer weight of the unit and handling. The outdoor portion of the split system is typically straightforward without many complications. The indoor portion is complicated by access to the location, brazing, pressure testing, and greater car needed to prevent moisture issues.
How Can I Tell What I Have
You should not feel bad if you are not sure whether you have a split system or package unit. You are in the minority if you know. The easiest way to tell is by looking at the outdoor unit.