The unit heater mainly contains air heater and fan, the air heater radiating, and then fan sent warm air out, make indoor air temperature can be adjusted. The air heater is composed of spiral finned tubes. For example, steam unit heater radiating coil is used Aluminium strip special equipment enlace around seamless boiler pipe wall thickness of φ 21.5, distance is 2.5mm, coil and heating medium flowing pipe is integrally welded structure, the heater work under the pressure of 116PSIG.