A number of intergovernmental agreements, the most important of which are the Paris Agreement (UN Framework Convention on Climate Change) and the European Green Deal, provide for resource efficiency and the reduction of greenhouse gas and particulate matter (PM2.5, PM10) emissions to 2030 (short-term program to reduce emissions by at least 55 %) and to achieve emissions-neutral production, transport and household activities by 2050. Latvia's National Energy and Climate Plan for 2021-2030), climate policy, including a policy aimed at significantly reducing GHG emissions and increasing efficiency in the household sector. Achieving these climate policy goals requires both a change in human habits and more efficient technologies. This article discusses one of the technological solutions that can reduce both greenhouse gas emissions and the release of PM2.5 and PM10 from individual heating systems in private homes and small commercial facilities. Calculations of electrical energy production with external combustion engine based microcogeneration system for household self-consumption will be done. The technology involves the production of heat from biomass or other types of renewable energy sources while generating electricity for self-consumption. Conclusions of CHP mode impact on boiler thermal efficiency will be done. Impact of fuel moisture and combustion regime to system overall efficiency will be done.