## 1 Introduction
In general, ZEBs use two design strategies: (i) reducing the need for energy use in buildings (particularly for heating and cooling) by more energy-efficient technologies, and (ii) using renewable energy and other technologies to meet the minimal energy needs [22; 23; 24; 25]. Since on-site energy generation options are often restricted, most ZEBs require energy conservation in order to be sustainable (for example, sufficient space for solar systems in high-rise building development) [26]. Many developed and developing countries have specific building energy and design requirements based on their respective environments and climates that meet, among other criteria, their respective design and construction method requirements [27]. Since architects and engineers believe that greater energy efficiency in buildings starts with design, the majority of them stay motivated with respect to their building designs in advance and work to design measures to achieve sustainable goals [28]. In terms of improved sustainability and energy efficiency, for example, research showed that homebuyers want more energy and resource efficiency, but they lack effective contact with builders, there is insufficient knowledge, and their choices are too small [29]. New energy-efficiency provisions have been thoroughly studied and debated, and these issues may have an effect on local budgets. In addition to efforts toward sustainability, the use of light-emitting diodes (LED) in indoor lighting instead of old incandescent bulbs has significantly contributed to an increase in renewable energy and energy savings [30; 31]. This area has been thoroughly researched over the last fifteen years, but other studies have analyzed the research on other forms of energy, including new sources of energy, and studies have been conducted to compare them to what was previously studied in structures and buildings' use of them [32]. Many researchers have agreed on the importance of ZEBs, for example, in gaining access to the skills required for advanced technology design, growth, and maintenance, as well as creative building and settlement design solutions [33]. Environmental benefits of design solutions are thought to result in lower overall energy use and carbon emissions, the use of community energy generation and management technologies, and so on [34]. Much research on ZEB has been carried out by Italian scientists. For example, [PERSON] et al. [35]assessed the possibilities of obtaining ZEBs in a Mediterranean climate by using only on-site renewable energy. As a result of the growing demand for ZEBs, further research in this area is needed. Previous review studies in this area [36; 37; 38] have made important contributions but have a number of limitations. For instance, [PERSON] et al., [39] performed a bibliometric study but restricted it to the diffusion of energy efficient technologies in European residential buildings. Furthermore, a recent study was conducted by [PERSON] et al. [40] but with an emphasis on renewable energy sources. In light of these findings, further research into the role of ZEBs and energy efficiency in achieving sustainability is needed. Therefore, bibliometric research was carried out in order to explore ZEBs and energy efficiency towards sustainability. Therefore, the objectives of this study are: research question 1 (RQ1. ): What is the annual publications' trend related to ZEBs and energy efficiency towards sustainability? RQ2: Which journals publish studies that contribute towards ZEBs? RQ3: In which context (country) were the studies conducted? RQ4: What are the new techniques, emerging trends and future research needs towards sustainability? Additionally, an example of a low-energy single-family building located in Poland is presented and its energy characteristics were determined on the basis of energy consumption measurements.