<p>The demand in energy requirement is met by combination of renewable and non-renewable sources. The scarcity and stringent emission norms of fossil fuel usage make the researcher toward the utilization of renewable sources. The use of solar energy attracts wide application due to its availability. The flat plate collectors are one of the energy-absorbing medium to improve solar efficiency by employing diverse nanofluid. The alumina and copper oxide nanofluids are used in this study due to its superior performance and its attracting thermophysical characteristics. Most of the studies covered the heat transferred and collector efficiency of FPC with various nanofluids. Very few studies covered the energy and exergy importance in heat transfer applications. In this work the energy and exergy analysis of two nanofluids (0, 0.1, 0.2, 0.3 and 0.4 mass fractions) are investigated to find the energy lost to environment, dead exergy and entropy generation with a flow rate of 3 L min^–1. The thermal conductivity of CuO and Al₂O₃ was found to be 64.93% and 63.96% higher than water. This improvement in the thermophysical properties of nanofluid finds wide application in the heat transfer field. The exergy efficiency of CuO and Al₂O₃ nanofluids was 48.2% and 48.79% higher than alumina at 0.4 mass fraction. The destructed availability of CuO and Al₂O₃ was 6.22% and 6.01% lower than base fluid at 0.4 mass fraction. The entropy generation of CuO and Al₂O₃ was found to be 12.11 and 6.48% lower than water due to the better heat augmentation of nanoparticles. The use of nanofluids improved the heat transfer rate and collector efficiency compared to water.</p> Graphical abstract <p></p>