High cost of building ownership and rent cause abandonment of large turn-of-the-century buildings, such as the Railway Exchange Building (Butt, 2014; Kukuljan, 2018). In Saint Louis, Missouri, vacancy in this category exceeds 1.2-million square feet and blights entire neighborhoods (Barker, 2019; Berg, 2010). Comparing the energy use of the building in its present state against one rebuilt for energy efficiency quantifies the cost disadvantage (Weng, 2012). Applying state-of-the-industry technology to improve the energy efficiency and thus the economics of a historic structure advances the Restoration and Improvement of Urban Infrastructure (Morgan, 2016; National Academy of Engineering, n.d.). Installing energy efficient LED fixtures proves to be a cost-effective solution for reducing the energy needs of the Railway Exchange Building. Reduced operating costs improve the viability of the Railway Exchange Building, other similar buildings, and their surrounding areas.