PTAC Alternative: Fujitsu's Split Terminal Heat Pump
Fujitsu Split Terminal Heat Pump (STHP) is a state-of-the-art PTAC alternative. It is a high efficiency minisplit type system that is designed both for retrofit in existing installations and for new construction. It consists of a wall mount indoor fan coil and an outdoor compressor unit mounted in a sleeve in the exterior wall. The physical size is the same as a PTAC, so the compressor unit fits perfectly in a 42" wide PTAC opening. Since the STHP from Fujitsu uses advanced inverter compressor technology, it has many advantages compared to legacy PTACs.
The white paper found here details the benefits, when compared to PTACS, of higher energy efficiency, lower noise levels, and more comfortable air distribution.