Renewable energy sources, such as solar, wind are either intrinsically DC or converted to DC for all general applications. As a result, before linking with a typical AC grid, a DC to AC conversion stage is necessary, which reduces the efficiency of the system. Presently, many loads are intrinsically DC loads, hence there is a further conversion from AC to DC is needed before utilization. Due to the intermittency of renewable energy, a storage system, typically a battery for building applications which is again a DC load/source, is needed for stable operation. If a DC distribution system is used between these sources, load, and storage, the repeated DC/AC and AC/DC conversions can be minimised, enhancing the system efficiency. Since these components in the present study are located inside a building, the Low Voltage DC (LVDC) guidelines specified by “IS 16711: 2017” are considered. The primary goal of this study is to develop a methodology for analysing Net Zero Energy (NZE) implementation using LVDC. This includes the location-specific and building-specific details. The procedure provided in this research provides the framework for solar-powered DC Nanogrid designers to predict the optimum battery size and solar PV size, to attain NZE with the better Net Present Value (NPV) and maximum battery life. This approach has been adopted for optimising the parameters for a typical residential and a commercial building located in a tropical monsoon climatic region. The results clearly demonstrate the benefits of connecting a solar PV source to a commercial building with a higher daytime load than a residential building with a peak load during non-sunshine hours.