A light shelf is a device that redirects sunlight to provide uniform and improved illumination. Increased daylight illuminance reduces electrical energy consumption (20% to 60% based on conditions). Additionally, it blocks direct sunlight and reduces the heat generated by the artificial lighting system. Although energy savings studies have been conducted on light shelves, no detailed investigation has been done so far to study the heat transmitted. There is a concern that the heat reflected from light shelves will increase the cooling load inside a building. In this study, experiments were conducted under controlled conditions to understand the heat transmission characteristics of light shelves. Various environmental disturbances affect the accurate determination of the components of heat reflected by a light shelf. A methodology to quantify the reflected radiation using experimental data has been developed in this research. The experimental investigation revealed that the secondary heat transmitted because of the heat absorbed by the light shelf is the major component, compared to the heat reflected directly by the surface of the light shelf. This result helped to develop a strategy for controlling the heat transmitted by the light shelf, that is, by actively cooling the light shelf. Experiments indicate that this could reduce 10% of radiant heat transmitted. Finally, a theoretical model of heat transmitted by light shelves has been developed in this research. The model was calibrated with the experimental data, and it reasonably predicts all the experimental results. The model is able to reproduce the trend in experimental data with good accuracy.