Vertical Stack water source heat pumps (WSHP), from 3/4 to 3 tons, are designed in multiple discharge air arrangements for use in multi-floor apartments, office buildings, hotels, and nursing homes where space is a premium. Using environmentally-friendly R-410A refrigerant, Vertical Stack units are readily available in full cabinet design for new installations, or as a stand-alone chassis design for quick change outs in replacement applications. EC motors, vibration isolators, compressor blankets, and insulated cabinet/chassis packages create quiet operation for sound-sensitive applications. A host of selectable options provide consulting engineers, contractors, and service engineers with highly-serviceable components, and efficient and reliable operation.