International organizations, European Union, as well as countries on governmental levels are taking part in reduction of pollutants from different sources, including combustion equipment, by setting emission limits and boundary values for different pollutants such as carbon dioxide, carbon monoxide, sulfur oxides, nitrogen oxides and particulate matter. Each solid fuel household boiler technology has to include electric precipitator according to EU Eco-design Directive. A fog unit is a novel flue gas treatment technology made for small capacity combustion units. First experiments have been made in the fog unit experimental stand and results are analyzed in detail. The capacity of the fog unit reached during experiments was between 1.02 kW and 3.11 kW, showing efficiency from 5 % to 15 %.