传统上，整体式（单件式）空调的效率等级低于可比分体式（2件式）空调。即使两台机组使用相同的压缩机和膨胀装置类型，效率也存在相当大的差异。这项研究确定，大约5%的效率会降低。离子是单件系统配置的固有特性，而10%到15%的降解可能是由其他设计因素造成的。引用:ASHRAE交易，第88卷，第2部分，加拿大多伦多

Package (single-piece) air conditioners have traditionally had lower efficiency ratings than compa-rable split (2 piece) units. The rather sizable differences in efficiency are common even when the same compressor and type of expansion device are used in both units. This study determined that approximately 5% efficiency degradat.ion is inherent to the single-piece system's configuration, while 10 to 15% degradation may result from other design considerations.