OPTIWARES is a joint CCES-CCEM project focusing on wood combustion. Wood combustion and other biomass combustion represent renewable energy sources, and contribute to reduce global CO2 emissions if the biomass stems from sustainable agriculture and forestry. On the other hand, biomass combustion inherently produces high emissions of particulate matter. These aerosol particles exert a climate forcing and have adverse health effects, affecting population morbidity and mortality. Therefore, the four key objectives of OPTIWARES are: (1) to assess the influence of wood burners on air quality, (2) to improve the application of energy conversion systems using wood, (3) to assess the regional climate effect of wood combustion, and (4) to calculate the external costs of the various types of wood usages. The results will be made available to the involved industrial partners, enhancing their competitiveness in the market in Switzerland and worldwide.