Generally, space heating and hot water providing are done by combi boilers. Different types of combi boilers are available. In the recent years condensing combi boilers have been introduced that have high energy efficiency in comparison with conventional types. In the condensing type combi boilers, an additional heat exchanger is utilized to recover energy form flue gas. In this study the effects of combi boiler type on pollutant gas emissions have been experimentally analyzed. In this regard three different combi boiler including conventional, condensing and full condensing type combi boilers have been selected in the experiments. In addition, the experiments have been done in different temperatures to investigate the temperature effect. The obtained results showed that in all temperatures using condensing and full condensing combi boilers reduced CO2, NO and NOx gas emissions considerably. Also, by analyzing combi boilers emissions in different working temperatures, it can be said that in low temperatures CO2 emission reduction in condensing combi is higher than its reduction in high temperatures in comparison with conventional one.