This research focuses on the development of an economical novel sensible heat storage material for performance improvement of a solar air heater purposely for space heating and drying operations under slightly cold environments. For this, a total of three models were developed. Model-I is a conventional air heater to compare the results of other studied models. Model-II carries a bed of the black-painted pebble stones in a uniform layer and Model-III performs on a newly developed heat storage medium that was prepared by mixing the black cement into carbon black powder in a ratio of 15:85. This material was used over the absorber in the form of tiny cylindrical-shaped geometries. All models were experimentally investigated on different days in October and November under three different configurations on natural convection. Model-III was found to be an optimized model of air heater. The results of the study showed an average percentage improvement in Model-III’s exhaust temperature was observed at about 9.8% and 9.27%, in thermal efficiency at about 24.2% and 8.7%, in heat transfer coefficient at about 47.98% and 58.37%, and in the overall heat loss coefficient at about 1.15% and 6.56 % compared with Model-I and II on natural convection trials during November. The exhaust temperature and duration of supplying hot air (8 to 8.50 h) were observed to be improved for Model-III compared with other studied models. Model-III is a cost-effective system for adoption and much more efficient for use. Thus, it is recommended for space heating and drying operations.