The simultaneous impact of a building's electricity consumption and thermal performance is analyzed in this paper by taking a thermal model of a retail building located in Ranchi, India. A Baseline design of retail building having a rectangular footprint area is compared with four buildings with different footprint areas (Rectangular, T, L, H and U), in the South-West orientation. The thermal models for lighting of retail building are developed using eQuest software, and results obtained were validated experimentally. Intensity of light is reduced by 35% in baseline building corresponding to the amount of energy saved by upgrading to a T8 fluorescent fixture from a T12 fluorescent fixture. Average daylight factor of retail building in hot summer was found to be 34.80% experimentally and 28.98% through simulation. Based on energy consumption it is found that, for temperate buildings with rectangular footprints, buildings with L footprints, and buildings with H footprints are preferable when targeting net-zero energy status. The results encourage architects and engineers to work out an effective framework to enhance the use of natural illumination energy and suitable lighting according to buildings layout.