On July 13, 1869, Benjamin Sturtevant was granted Patent #92490 covering an air-blast apparatus, consisting of the combination of a rotary blower and a heater constructed for mutual operation. This marked the beginning of the modern air-blast apparatus as applied to heating, ventilating and drying applications.
In addition to central hot blast systems, individual units were designed to meet heating requirements in industrial plants and buildings with high ceilings and floor areas. They could be floor, wall or ceiling mounted.
It was nearly a full decade after Nesbitt Co. introduced the first unit ventilator in 1917 that Sturtevant brought out their version, though they patented a unit ventilator as early as 1915. As long-time believers in the Central Air System, they viewed the initial units as too bulky and noisy to be seen as a viable alternative. With the creation of a light-weight copper heating surface,(developed by Aerofin Corp. which Sturtevant co-founded) in the 1920s, these issues disappeared and Sturtevant jumped into the fray. Originally developed for schools, unit ventilators would be in great demand in public and private buildings.
Heating equipment was manufactured through the 1950s.