A heating and air conditioning package unit is an all-in-one system. Package units contain all the necessary components in a single unit that sits outside the home. This common design offers a number of benefits many homeowners consider advantageous compared to other heating and cooling systems. Since all the essential parts of a package unit are housed in one cabinet placed outside the home, no interior space is required for installation. It is also not necessary to vacuum the lines or charge the unit with refrigerant, so a service technician requires less time on site to activate the systems.