In the present research, thermal efficiency and the amount of pollutant emissions of a metallic porous burner with a heat exchanger were investigated experimentally. A very important issue about these burners is the stability of flame on the surface of the porous medium. In the present research, through creating a surface flame in the porous medium, the performance of the burner was observed. In this article, by changing the factors like thermal power and equivalence ratio, thermal efficiency and the amount of pollutants were studied. Results showed that the best performance of the burner occurred when the equivalence ratio was 0.8. The maximum thermal efficiency of 39.43% occurred at an equivalence ratio of 0.8 and thermal power of 100 kW. As thermal power increased, the amount of emitted nitric oxide (NOx) increased. Approximately at all measured conditions, the amount of emitted NOx was less than 15 ppm. Also, the amount of emission carbon monoxide (CO) at an equivalence ratio of 0.8 and thermal power of 100 kW was the lowest. In this research, results of the porous burner were compared to the free flame burner and the results revealed that in the best condition, thermal efficiency was improved up to 5.8%. Accordingly, the amount of emitted NOx was reduced strongly but the amount of CO of the porous burner was much more than the open flame burner.