Renewable sources play a crucial role in the decarbonisation process of the current linear economy, aimed at reaching the 2030 climate objectives and fulfilling the EU’s long-term strategy of achieving carbon neutrality by 2050. All economic subjects, including households, can contribute to the Green Deal goals. The main goal of this paper is to evaluate households’ consumption of energy sources for heating purposes in the Czech Republic in the period 2003–2020 and depict possible drivers of switching to biomass. For this, various data were collected, such as data published by the Czech Statistical Office, ministries, and other national authorities, as well as data from Eurostat. Concerning methods, data analysis, correlation analysis, and regression analysis were used. Different models focus on the substitution effect, rebound effect, and behaviour of different kinds of households. The results show a substitution effect connected with the consumption of coal, electricity, and biomass for heating purposes. Many households substituted coal for biomass in the observed period. On the other hand, the environmental impact of such substitution is not significant, as carbon emissions and emissions of other pollutants are stable. The substitution of fuels should be accompanied by technological change, e.g., improvement of combustion boilers. Moreover, households of pensioners are the key economic subjects with the highest impact on biomass consumption for heating purposes. Against this background we recommend policies to support households in replacing their boilers for more environmentally friendly ones.