The building sector significantly contributes to electricity consumption due to the need for cooling and heating to ensure thermal comfort for occupants. In rapidly developing countries such as India, the building construction sector is experiencing swift growth, which will further increase energy demands in the future. The embedding of phase change materials (PCMs) in building envelopes has been extensively researched to enhance thermal comfort and reduce the heating and cooling loads. In India’s tropical climates, substantial energy is consumed for cooling operations in buildings, necessitating effective solutions. This study explores the potential of capric acid, a fatty acid, to reduce the thermal energy requirements of a building, situated in New Delhi by integrating it at various locations within the south-facing wall. The thermal characteristics of capric acid (melting temperature, crystallization temperature, and latent heat capacity in melting and crystallization) used as input to Type 1270a were determined through differential scanning calorimetry. Numerical simulations were conducted using the Transient System Simulation Tool (TRNSYS-18) software, incorporating Type 1270, a specialized module for PCMs. Weather data for New Delhi, India, were sourced from TRNSYS libraries, utilizing typical Metronome weather data, with Type 49 implemented for ground coupling.