Use of an Air-Cooled Condensing system, to condense turbine exhaust steam from the steam cycle of combined cycle plants, coal-fired plants, and various other plants using steam to generate electricity, has gained acceptance. However, as electricity generation is privatized, building plants at low cost has been the priority rather than the performance. This paper discusses the impact of velocity consideration in the design of air-cooled condensers. The velocity at design point and the change in velocity affect the steam duct design and the tube bundle design. As the ambient temperature varies, it affects and/or limits the range of turbine operation. This, in turn, can improve or adversely affect the plant electric power output. The velocity also has an effect on the condensate temperature. The reheat of the condensate requires energy which is redirected from generating capacity which is often ignored.