Liquefied petroleum gas is a widely used fuel in household and commercial cooking applications. Various methods are implemented for improving thermal efficiency of gas burners by means of geometric modifications to the burners. The present study is conducted on an annular multi-slot burner with LPG as fuel and air as oxidizer. Annular multi-slot burner gives a wide range of combinations for air-fuel mixtures to be supplied to the combustion zone. The study focuses on improving thermal efficiency purely by feeding various combinations of air to fuel ratios in various slots and studying their effects on flame structure. Experiments are carried out on some of the possible combinations and respective thermal efficiencies are reported and compared with conventional burners.