Very high emissions of PCDD/Fs up to 1300 microg TEQ per ton of coal were measured during combustion of commercial high chlorine content coal in a stove. A pronounced effect of the temperature profile in the chimney on PCDD/F emissions was identified, suggesting formation in the chimney. Emissions of PCDD/Fs were one order of magnitude higher with an insulated chimney than with a non-insulated one. Insulation of the chimney did not influence the emissions of regulated pollutants and PAHs. Under laboratory conditions, the thermal properties of the chimney usually differ from those in residential dwellings. For that reason it is concluded that PCDD/F emission measurements performed under laboratory conditions may not be representative for derivation of emission factors in emission inventory compilations. Thus the emission factor of 1300 microg TEQ per ton of coal (40000 microg TEQ/TJ) represents the maximum value for individual stove emissions. Complementary air dispersion modelling and congener profile based receptor modelling performed in the Krakow area, Poland confirm a high contribution of the residential combustion to the ambient air PCDD/F levels in that area and indicate an emission factor for coal combustion in stoves in the order of 100 microg TEQ per ton (3000 microg TEQ/TJ).