Pakistan is facing severe natural gas crisis and all industries are suffering. Hence all efforts should be made to save natural gas from domestic use. The conventional radial flow natural gas stove burners have low thermal performance because of high convective and radiation heat losses. Swirl flow stoves have comparatively high thermal efficiency. The shape of vessel has significant effect on the performance of stoves. A swirl stove with two heating vessels (a pan and a pot) was used for experiments. Three different flame covering draft tubes were tested i.e. Ceramic mould, Aluminum draft tube and polished steel draft tube. Thermal efficiency was checked by heating water from 30 C to 80 C and determining consumption of natural gas. Ceramic mould increases thermal efficiency of swirl stove from 36 to 39.1%. The aluminum foil with ceramic mould leads to an improvement of 45.1%. Aluminum draft tube, polished steel draft tube and ceramic mould wrapped with aluminum foil showed 2.6, 3.8 and 5.6 % increase in thermal efficiency respectively. The work is useful for designing modified burners and stoves to conserve natural gas.