Central AC System GuideA split-system central air conditioner divides its equipment between an outdoor unit and an indoor coil or air handler, while a packaged unit houses the cooling components in a single outdoor cabinet. This comparison sticks to what U.S. government sources publish about each configuration. It does not pick a winner.
How to read this comparison
ENERGY STAR and the Department of Energy both recognize packaged and split configurations, and they publish separate efficiency criteria for each. Those criteria are stated in SEER2 and EER2, the metrics standardized in 2023.
Every figure below is quoted from an ENERGY STAR or DOE page. Because the two programs set different thresholds for the two configurations, those thresholds are the clearest documented point of comparison.
Split systems in the federal criteria
A split system places the compressor and condenser outdoors and the evaporator coil indoors. ENERGY STAR publishes the SEER2 and EER2 a split-system central air conditioner must reach to qualify, and DOE includes split systems in its acquisition guidance.
These figures are the documented efficiency floor a qualifying split system must clear.
Packaged units in the federal criteria
A packaged unit houses the compressor, condenser, and evaporator in one outdoor cabinet. ENERGY STAR publishes a separate SEER2 and EER2 threshold for packaged central air conditioners, and DOE includes single package and gas/electric package units in its guidance.
These figures are the documented efficiency floor a qualifying packaged unit must clear.
Where they differ on paper
The clearest documented difference is in the ENERGY STAR eligibility thresholds. Split-system central air conditioners must reach SEER2 17.0 and EER2 12.0, while packaged central air conditioners must reach SEER2 16.0 and EER2 11.5, so the split-system requirement sits higher on both metrics.
Beyond the thresholds, the DOE FEMP guidance treats both configurations within the same acquisition program, covering single package, split system, and gas/electric package models under 65,000 Btu per hour on single-phase current. The configuration difference is where the equipment lives, and the federal difference on paper is the separate SEER2 and EER2 bars each must clear.