Unit Heater 3 : A self-contained heating appliance, which may or may not include a floor-mounted or suspended integral fan, intended for heating only the space in which it is installed
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}