Our paper discusses a scenario for adapting residential buildings to the requirements of the EU climate and energy package. It analyzes the option of reducing pollutant emissions to ambient air by switching to alternative energy sources in a typical single-family residential building. The most common sources of energy in central heating and ventilation systems and water heating systems were compared, and the analyzed energy carriers were brown coal, electricity supplied by the electric power grid, biomass, natural gas, heating oil, and combined production (which relies on various energy carriers). In the examined scenarios, special emphasis was placed on carbon dioxide emissions and the value of the equivalent emission factor.