Definition
A split system is an air conditioner or heat pump divided between two cabinets: an outdoor condensing unit containing the compressor and condenser coil, and an indoor furnace or air handler containing the evaporator coil and blower. Insulated copper refrigerant lines and low-voltage control wiring connect the halves, and the pair is rated together as a matched system.
Also called: Split-system AC, Split heat pump
Why it matters to you
Most forced-air homes in SW Washington and the Portland metro use a split system, with the indoor half usually a gas furnace or air handler in a garage, basement, closet or crawlspace. Because efficiency ratings apply to the matched indoor-outdoor combination, a new outdoor unit paired with an old coil can fall short of its advertised rating.
Practical guidance
When replacing either half, ask whether the new outdoor unit and indoor coil are a certified matched combination and which refrigerant the new equipment uses, since many new systems use A2L refrigerants such as R-454B or R-32. Line-set, refrigerant and electrical work is licensed technician work.
About this definition
Written by the Home Energy Group team — a family-owned HVAC company celebrating 25 years of comfort & care across SW Washington and the Portland metro, licensed in Washington (WA LIC# HOMEEGI003J7) and Oregon (OR CCB# 184255). Definitions inform; an on-site diagnosis decides.
