It's not simple. In places like industrial workshops, where people are
*working* and thus generating some of their own energy, any sort of traditional space heating may be impracticable perhaps because of ventilation for welding or other fumes, or because large doors are open at the end of the bays. But this sort of electrical heating, alternatively from high-mounted radiators on steam mains can make it quite practicable to work, including having hands on to cold steelwork, in air temperatures no more than 5 - 10 degrees C (significantly below "Factories Act" temperatures).