Of all the European Union's member states, Poland has the most acute ambient air pollution problem. An urgent transition from solid-fuel heating (e.g. coal and wood) in the housing sector is required to improve air quality in the country. National regulations still allow the sale of solid fuels for heating, but some municipalities impose local resolutions with binding deadlines for solid-fuel bans. A realworld study covering 422 apartments in heritage tenements in Wrocław is presented. A link between domestic solid-fuel usage and tenure type is identified: solid fuels prevail in social housing. The transition to other forms of heating will adversely affect the inhabitants already vulnerable to fuel poverty. Solid fuel proves to be the least preferred heating option and is linked to substandard living conditions. Fuel poverty vulnerability for low-income households is established based on cost analysis for different heating options, thermal retrofit strategies, internal temperatures and apartment sizes. The results indicate that climate injustice is likely to occur for the poorest inhabitants due to their inability to afford increased costs. Policy implications to address this injustice are needed to ensure the transition from solid-fuel heating will avoid new vulnerabilities. Policy relevance Domestic solid-fuel combustion for heating purposes is linked to poor air quality in urban areas in Poland. Heritage tenements are the most technically deprived building stock and their inhabitants are already vulnerable to fuel poverty. To improve air quality and respond to climate change, solid fuels need to be substituted with less polluting but more expensive heating options. Potential climate injustice (harm) is likely to occur if the poorest inhabitants cannot afford to heat their homes due to a ban on solid fuels. The change of heating needs to be combined with additional support (thermal retrofit and appropriate pricing of alternative fuels). Air quality-driven polices focused on solid-fuel eradication should not ignore fuel poverty already experienced mainly by social housing residents using expensive electric heating on a standard tariff. Fuel poverty has a gender aspect related to the gender pay gap that needs addressing.

This paper demonstrates the need and potential for using waste heat recovery (WHR) systems from infrared gas radiant heaters, which are typical heat sources in large halls, due to the increasing energy-saving requirements for buildings in the EU and the powerful and wide-spread development of the e-commerce market. The types of gas radiant heaters are discussed and the classification of WHR systems from these devices is performed. The article also presents for the first time our innovative solution, not yet available on the market, for the recovery of heat from the exhaust gases of ceramic infrared heaters. The energy analysis for an industrial hall shows that this solution allows for environmental benefits at different levels, depending on the gas infrared heater efficiency, by reducing the amount of fuel and emissions for domestic hot water (DHW) preparation (36.8%, 15.4% and 5.4%, respectively, in the case of low-, standard- and high-efficiency infrared heaters). These reductions, considering both DHW preparation and hall heating, are 16.1%, 7.6% and 3.0%, respectively. The key conclusion is that the innovative solution can spectacularly improve the environmental effect and achieve the highest level of fuel savings in existing buildings that are heated with radiant heaters with the lowest radiant efficiency.

The renewable and waste heat sources implemented for the preparation of domestic hot water (DHW) allow for energy conservation and environment protection along with resource savings and economic benefits. The solutions, including non-conventional sources, are especially demanded in large halls in which energy and water consumption are crucial for maintenance costs. In this article, energy analysis of a DHW preparation system for workers’ hygienic purposes in a industrial hall was performed. The DHW preparation system consisted of three sources: a flue gases heat exchanger as the waste heat source, solar collectors as the renewable heat source and a gas boiler as the conventional source. In the analysis, data of a variable-temperature supply of water and hourly water consumption data from the measurements in the industrial hall, located in Poland, were applied. The results for all of the 8760 h of one year were examined. The analysis outcomes show that implementation of non-conventional sources can supply 81.4% of energy needed for DHW preparation, avoiding a lot of running costs; just 18.6% of heat demand had to be obtained from a gas boiler. The analysis also confirms that the system may operate correctly when the appropriate device size is applied, along with a proper control strategy that avoids overheating water and uses alternative sources.