Economical and efficient use of energy is promoted around the world as a model of conscious care for the environment in which we live. A mere change of habits in the use of energy can reduce its costs by 5% to 15%, and investments in energy-saving technologies can pay for themselves after just a few years. This case study shows how significant steps can be taken in saving energy in the building of public utility buildings through deep thermomodernization using renewable energy sources—compressor heat pumps and photovoltaics. The article presents a comprehensive thermomodernization of a school building made according to Polish regulations. A detailed description of the tested object is given, and the calculation procedure is described. Next, the optimal investment variant and ex post analysis are described. The implementation of these projects significantly improved the energy efficiency of the building and generated final energy savings of 80%, which will significantly reduce the school’s operating costs. Thanks to the applied improvements, it was possible to save 72.30% of thermal energy in the building, which directly translates into lowering the building’s operating costs. The improvement of energy efficiency indicators ranges from 66% for usable energy to almost 85% for non-renewable primary energy. Furthermore, by reducing the demand for energy used in the building by nearly 74%, we see a reduction in CO₂ emissions. The methods used were desk research and an extended case study of Poland, a country facing a number of problems related to energy prices during the energy crisis. In this article, we identify the challenges faced by Poland due to its geopolitical situation, and the solutions introduced to the difficult situation in the energy market come in the form of the thermomodernization of buildings. It was on this basis that Poland was selected as a case study.

Three-quarters of global greenhouse gas emissions come from burning fossil fuels for energy. To confront climate change, the world must move away from fossil fuels and decarbonise its energy systems. In the light of European Union documents, decarbonisation signifies the elimination of CO₂ emissions on account of their harmfulness to the environment. The European Union is planning that by 2030, these emissions will be 40% lower in comparison to 1990. A fundamental query arises here: do the achievements of EU countries give cause for optimism in this regard? The aim of the study is an attempt to determine the tendency of changes concerning energy decarbonisation as well as to distinguish typological groups of bodies (EU countries) with similar dynamics in the researched phenomenon. Trend functions and the distance matrices of the growth rate of the researched phenomenon were used for the dynamic classification. The conducted research confirmed that EU countries indicate spatial differentiation in terms of CO₂ emissions. It is related to the general socio-economic development of countries, their level of industrialisation, the quality of their natural environment, their degree of urbanisation, etc. The most favourable situation, in terms of the analysed phenomenon, i.e., the largest average decrease in CO₂ per capita in the analysed period, was characteristic of Ireland, Greece, and Cyprus. On the other hand, an adverse situation relating to an increase in the indicator occurred in five EU countries, specifically in Luxembourg and Lithuania.

Improving energy efficiency includes a number of measures implemented as part of the greening of the energy industry, which in turn is a prerequisite for the creation of a sustainable energy industry to ensure energy and environmental security for the world. Despite the adoption of the EU directives on energy efficiency, there is still insufficient public awareness in this area in Poland and Slovakia. This is particularly surprising because improving energy efficiency not only brings national and global benefits, but also has a significant impact on the well-being of individuals and households. The main purpose of the paper is to analyze the national policies of Poland and Slovakia, which are based on the European Directive 2012/27/EU on energy efficiency, and which introduce new measures aimed not only at increasing energy efficiency, but also at increasing the well-being of households and individuals. Methods of desk research and content analysis were used. The current situation in both countries is illustrated by case studies that document the administrative process (Slovakia) and the calculation of energy savings (Poland) when using renewable energy sources in the case of family houses.

The increase in energy demand requires urgent investments in sustainable energy. It is vital to the success of the 2030 Agenda, adopted by the United Nations General Assembly. The article aimed to assess the situation of the European Union countries with regard to energy use. Indicators related to the implementation of SDG7 and environmental and resource productivity of the economy were adopted for the study. The research presented in this article fits into contemporary debates on the effectiveness of implementing one of the SDG7: ensuring access to affordable, reliable, sustainable, and modern energy for all. The analysis included 26 countries that have been in the European Union since 2010. The study’s originality lies in the use of primary data obtained from the Eurostat database for three research periods: 2010, 2015, and 2020, which will allow for assessing the situation of the surveyed EU countries in the area of energy use. In order to achieve the research objective, selected methods of descriptive statistics and vector measurement were used. The application of a vector measure made it possible to rank the studied countries in terms of efficient energy use. Based on the results obtained, there is a significant variation in space and time in the evolution of the energy system of the European Union’s member states toward sustainable development. Rational energy use is primarily the domain of north-western European countries, with Sweden and Austria always leading the rankings. However, this does not mean that in these countries, in spite of their high position in the ranking, the levels of some indicators in 2015 and 2020 as compared with those in 2010 did not deteriorate. Due to this fact, attention should be paid to the energy use process and identification of signals responsible for deteriorating the outcomes. The research results can help diagnose the results obtained so far and correct the European Union’s climate and energy policy in the future.

Zero-emission buildings, which do not emit CO₂ or other greenhouse gases throughout their entire life cycle, play a crucial role in sustainable development and the fight against climate change. Achieving carbon neutrality in construction requires considering emissions associated with material production, construction, operation, as well as demolition and disposal. These buildings utilize energy-efficient technologies, renewable energy sources, and low-carbon materials, minimizing their environmental impact. The building sector accounts for a significant percentage of global greenhouse gas emissions, making it a key area for climate action. In Poland, where aging and energy-inefficient buildings prevail, the need for a transition towards zero-emission buildings is particularly urgent. This paper assesses the feasibility and hurdles of retrofitting existing buildings to achieve zero emissions by utilizing renewable energy systems like solar photovoltaic and heat pump technologies. The publication discusses the technical, economic, and legal aspects of this transformation, with particular emphasis on the Polish context and available support programs. The purpose of this publication is to disseminate practical knowledge and foster innovation among architects, investors, and decision-makers engaged in the development of a sustainable built environment. A key example is Net Zero Energy Buildings (NZEBs), which generate as much energy as they consume over a year through technologies such as photovoltaic panels, solar collectors, and heat pumps. NZEBs combine effective insulation, energy-efficient systems, and smart energy management to minimize consumption, and may even produce excess energy that feeds back into the grid. Despite challenges in construction and maintenance, the increasing adoption of zero-emission and NZEBs worldwide reflects their long-term ecological, economic, and health benefits. The focus of this publication is to analyze the potential for transforming standard buildings, as defined by current regulations, into zero-emission buildings powered entirely by renewable energy sources. This case study analyzes the energy potential of a residential building located in Krakow, Poland. The building’s energy efficiency potential was assessed through computer simulations using Audytor OZC software (version 7.0 Pro, Sankom), taking into account local climate conditions and building standards. The study analyzed the impact of various strategies, such as upgrading thermal insulation, using energy-efficient windows, and installing photovoltaic panels, on energy consumption and CO₂ emissions.