An assembly of electrically-powered devices designed to heat a patient's whole body to compensate for the loss of normal body heat. The system includes a flat pad with electrical heating elements designed to be placed under or over the patient, and a control unit to regulate the heat; some types may be capable of monitoring the temperature at the patient’s body surface. The pad is available in a variety of lengths, widths, and thicknesses to accommodate body size and applications (e.g., adult/paediatric, full-/partial-body). It is typically used in the operating room (OR), adult or neonatal intensive care unit (ICU), recovery units, or during neonatal transportation.