Abstract The Italian market of wood pellet and stoves is increasing quickly as, at the same time, the concerns about the particulate matter (PM) and gas emission products. Therefore, the assessment of their environmental impact is becoming an important issue. However, the emission factor from pellet stove measured according to technical standards does not provide representative data with respect to a real domestic utilization. This difference is a consequence of different operation and combustion conditions as well as the exclusion of unsteady state phases (e.g. ignition phase) from the standard measurement. In this study combustion tests were carried out simulating domestic utilization conditions of a pellet stove and a sampling methodology more representative of the real environmental impact of these devices. Higher concentration of PM, up to 72% more than those measured in steady state condition, was shown. A higher emission factor has been observed also for carbon monoxide (CO), total carbon (TC) and polycyclic aromatic hydrocarbons (PAHs) especially during unsteady combustion phases (e.g. ignition phase) which significantly affect the emission factor in particular when the pellet stove works for short time (less than 2 h).