The Horizontal Hideaway with Plenum (CPY) fan coil unit provides the same basic features on the CHY plus a return air plenum for above-ceiling mounting in closets, hallways or bathroom areas. The CPY design enables the unit to be adapted to installations requiring return air ducts or to be used as a return-air plenum with a unit-mounted filter and filter-rack assembly. CPY units are shipped from the factory ready for installation with the plenum section in place. No field fabrication is required. CPY units are designed with interchangeable panels so that the unit may be modified on site to accommodate a rear or bottom return. Standard CPY units are provided with a galvanized finish.