The authors of this article were guided by the desire to show the profitability of using renewable energy sources and to facilitate decisions for future investors as to their choice. The article classifies energy sources and methods for converting renewable energy sources (RES) and presents a technical comparison of two electricity supply systems: a photovoltaic system and a household wind farm for a selected building. A residential, single-family building, inhabited by a family of three, was adopted for analysis. Photovoltaics, the use of solar radiation energy to produce electricity, is classified next to wind farms as the most dynamically developing renewable energy technology. When analysing in terms of technology renewable conversion methods that provide us with electricity, the better installation is the photovoltaic installation. By analysing the cost of renewable energy conversion technologies that provide us with electricity, the photovoltaic system becomes more beneficial, because with a similar investment price we get a much shorter payback period than in the case of a backyard wind power station.

Persistent air pollution (SMOG) in large cities in countries based on energy and coal heating is a serious and growing problem. Improving air quality is currently the main challenge for the metropolises of Central and Eastern Europe. Despite intensive efforts, the average annual concentration of PM2.5 in this area exceeds the standard recommended by the World Health Organization (recommended standard – 25 μg). Data from environmental institutions show that, for example, in Kraków (Poland), the number of days with PM 2.5 concentrations drastically exceeding the permissible standards in the last year was 96. The article describes the method of controlling air purification in the apartment using automation devices, control software and applications available for smartphones, tablets and personal computers. The presented solution uses technologies that can use free (alternative) software, extending the functionality of devices and increasing the flexibility of the control system. The main goal is to maximize the comfort of home users and to minimize the cost of electricity consumption. Additionally, the existing air cleaning devices are adapted to the needs of the air cleaning control system.

The article analyzes factors that may have an impact on Occupational Safety in a construction company and the issues of work safety in construction were discussed. An attempt was made to analyze the management of work safety in construction companies in order to identify important factors and determine the significance of their participation in the occurrence of accidents at work. The research was carried out on the basis of data obtained from the register kept at the District Labor Inspectorate in Krakow. Cases which were discussed included accident protocols prepared pursuant to the law, as well as cases found in protocols of ad hoc inspections carried out on construction sites. There were quantitative and qualitative features in the analyzed data set. Logistic regression was used to analyze the data to build the model. Such action made it possible to model and determine the significance of the influence of individual variables characterizing the way of managing work safety in construction companies, in the case of an accident. The results obtained, and in particular the significance of factors shown in the model, even not directly related to the construction site, may be an indication for creating a functional strategy in the enterprise. The strategy assuming: smaller number of accidents or adverse events, shorter downtime will build a reputation of an institution that cares for the employee. This will allow the construction company to become more competitive and shall attract the best professionals available on the labor market. The end result is the identification of key factors that have a direct impact on work safety and the competitiveness of a construction company.

The article discusses the technical condition of buildings. An attempt was made to compare the technical condition and the degree of technical wear of two multi-family residential buildings erected at the interval of 25 years. The list of such objects is intended to illustrate that even relatively young buildings may exhibit differing levels of wear and technical condition of building elements.

Investors are obliged to carry out construction processes based on the binding rules and regulations. However, these regulations are constantly evolving and subject to various attempts of improvement. Therefore, the aim of this article is an attempt to present the changes that have recently occured in the Polish process of construction process of a single-family residential building, in the context of proceedings before architectural and construction administration authorities. Basic legal acts regulating this procedure have been amended, such as: the Construction Law Act and the Regulation of the Minister of Development on the detailed scope and form of a construction design. Since these regulations have changed their provisions many times over the years, the article focuses on the changes that entered into force during 2020 and 2021. An additional aim of the article is to check and show how these changes were adopted by both investors and participants in the construction process, such as designers. In order to achieve this goal, a survey was conducted among them in Mał opolska region. The data concerning the submitted applications for permits for the construction of a single-family residential building, within the mentioned years, have been analyzed.