In this study two type of burner was used; swirl burner and radial burner. The thermal efficiency and emission of pollutant was observed on the basis of four parameters; nature of flow (swirl and radial flow), confinement of flame, primary aeration and loading height. During this study natural gas was used as fuel. Experimental results show that swirl motion cause for turbulence and lengthen the flame due to which residence time of flame increase as well thermal efficiency increase. In case of swirl flow overall efficiency which was to be observed was 39.5% while overall thermal efficiency was 37.4%. Swirl flow as well cause for the reduction of CO monoxide due to high temperature of flame than swirl type of flow. Confinement of flame is another parameter caused for the enhancement of thermal efficiency. Due to confinement of flame dispersion of flue gases in atmosphere become delayed causing to enhance overall efficiency. Swirl flow burner with confinement or shield have an overall efficiency of 41.5% while radial flow burner with confinement or shield have an efficiency an efficiency of 39.4%.  Metallic confinement or Shield and swirl motion on combined basis save about 10% consumption of natural gas as compared to open and radial flow. Supply of primary aeration causes to enhance complete combustion as well cause for the reduction of CO gas. Also due to primary aeration thermal efficiency increases and appearance of flame was changed from yellow to blue. In case of primary aeration supply temperature of flame was 895°C while in absence of primary aeration the color of flame was yellow as well temperature was 807°C. Loading height have an optimum value up to which efficiency increases after that loading height efficiency decreases. In case of radial flow overall thermal efficiency increases in the range of 1-2.8 cm while in case of swirl flow this optimum range is 1-2.4 cm.