Multi-port gas burners find applications in various industrial and domestic heating appliances. The multiple flame jets of the burners provide higher rate of heat transfer with uniform heat flux over a large area of the target surface. An extensive contribution to the design and development of energy efficient and clean combustion gas burners is reported by the scientific community. The involvement of combustion apart from the heat transfer makes the physical understanding more complex as compared to other heating methods. One of the most interesting things is that the combustion and the heat transfer phenomenon are associated with one another and the independent characterization of each will be unproductive. Present study investigates the thermal characterization of self-aspirating radial-type domestic gas stove burners. The heat transfer characteristics are studied for varied inner port swirl angles. An alternate methodology is suggested to evaluate the thermal performance of burners which gives more technical insights in comparison with conventional water loading test. The thermal efficiency from the conventional water loading method and the presented alternate method matches within ±2%. Among all swirl angles of burner ports, the inner port swirl angle of 10° produced higher Nusselt number and thermal efficiency. The efficiency is found to be increased by 7% by a simultaneous reduction in the loading height by 10 mm and by providing an inner swirl angle of 10°. © 2019 Elsevier Ltd