Sand, being an abundant and eco-friendly material, has the potential to serve as a cost-effective alternative for thermal energy storage systems. This study envisages the thermal energy storage capacity of non-plastic and low-plastic soils, and is compared with clays having varying liquid limit from 27 to 31%. A cubic prototype assembled with solder pot; tungsten coil and glass wool (insulation) were designed to ascertain the ability of various soil samples for their heat retentivity up to 200 ℃. Different intensities of heat and their storage properties were measured for the soil samples compacted in the prototype. The results show that soil-3 with WL-31% has the highest time of heat retentivity (585 min) among the four types of soils, whereas soil-1 with WL-27% has heat retentivity (550 min) almost equal to that of the sand sample. The soils retain heat for longer when their specific gravity, silt content, sand content, liquid limit, and OMC are higher. As the silt content increases in soils, the heat retentivity of soils also increases (1–5%) due to the net negative charge. The OMC obtained for the soil under study found to have a good correlation with maximum heat retentivity time of soil.