Solar energy is the natural resource of energy. Solar energy is rapidly advancing as an important means of renewable energy resource. The Sun is the source of all energy. The energy obtained from the sun is the most promising renewable energy sources since it is clean, safe and free. Solar power is the technology of obtaining usable energy from the light of the sun. Solar energy has been used in many traditional technologies for centuries and has come into widespread use. Applications of solar energy are commercially available and are used by millions of people in various parts of the world. One of the promising areas of the applications of solar energy is solar air heater. Solar air heaters are used for drying and space heating. Cultivation is one of the important occupations for the livelihood of the people in villages. Grapes, Tea, Cardamom, Pepper and Coffee are mainly cultivated in Theni District in Tamilnadu, India. Drying the products in a hygienic manner is one of the important processes in agriculture. We have decided to design a novel solar air heater and study the thermal efficiency of the air heater by varying the material of the collectors. Glass, Polythene sheet and aluminium foils are the various materials used to compare the efficiencies of the air heater. The main advantage of it is that no insulation material is needed. This type of air heaters can be used to dry the agricultural products which require hot air at low temperature ranges from 40 ° C - 100 ° C. This type of air heater can be utilized for various applications such as dehydration and drying. This would be beneficial not only in conserving the fossil fuels, but also in protecting the environment by the emissions of harmful pollutants and green house gases.