For creating comfort conditions, the use of conventional fuels as a driving force to pump heat could be avoidable, especially in domestic applications and in a tropical climate, where vapor compression refrigeration systems are mainly used to achieve cooling. Global warming is also a key concern due to carbon dioxide emissions, which increased rapidly in the last few decades. This situation in the cyclic process leads to increased load on compression-based systems because of growing both the installations and required temperature difference. A renewable source in the form of cold dark space at 3 K exists through the atmospheric window (8-13 µm) for cooling applications. The recently developed photonic radiative cooler having selective emissive surfaces (highly reflective in the solar spectrum and emissive in the atmospheric window) utilizes this renewable cold source for passive cooling and maybe a possible alternative to partially/fully replace the compression-based cooling appliance. In this study, the photonic radiative cooler is used as the roof envelope of a room and numerical simulation of the room is done using CFD tools to predict inside room thermal performance. This study also shows the comparison of inside room cooling requirements with and without the radiative cooler and temperature difference in both cases at rooftop nearly 30 °C impacts inside room temperature difference of 7 °C. A noticeable reduction in cooling load dependency on conventional appliances is observed with radiative cooler applied roofs. Also, it could be concluded that a simple ceiling fan may be enough for normal comfort conditions using the cooler. However, during peak summer and solar noon, requires the air conditioner but for reduced load and time span.