## 1 Introduction
This approach allows for long-term economic gains, reduced fuel import/supply costs, more efficient energy generation, and reduced emissions from renewable energy sources. When it comes to effective real-time monitoring and management of power chain data, this plays an important role in the process of increasing energy demand. Optimizing energy storage involves three primary parts:  
1. Energy sources including upstream refining processes;
2. Energy transfer processes comprising energy storage and distribution systems;
3. Energy demand in the building and transport sectors. Energy chain of suppliers and their distribution [14; 15]. IoT uses sensors and networked systems to detect and transmit information in real-time for rapid assessment and effective decision-making. It will also enable the energy sector's transformation into a decentralized system, namely a smart and optimized electricity grid. The automation, integration, and monitoring of production or non-production processes through the Internet of Things-based systems as well as communication technologies and installed sensors represents the backbone of the whole issue of energy efficiency [16]. When focusing on a comprehensive analysis of building energy performance data, preferably through Building Information Modelling (BIM) applications and sophisticated algorithms, energy consumption trends on the consumer and defined application side can be tracked and, thus, the energy consumption over different time periods can be managed better [17; 18; 19]. The European Union considers energy efficiency an important way to reduce its dependence on fossil fuels, protect the environment more effectively, and save on energy costs. The Energy Efficiency Directive became one of the most discussed topics in Europe in the last year; however, the draft Roadmap to a Low-Carbon Economy also takes savings into account. Developments Up to Now and Expected Steps in the Field of Building Energy Performance  
In the EU, approximately 40% of energy is consumed in buildings. At the same time, the buildings are the source of 36% of CO\({}_{2}\) emissions. Currently, approximately 35% of buildings in the EU are over 50 years old, and more than 75% of buildings are unnecessarily energy-intensive, with only approximately 0.4 to 1.2% of them being renovated each year (depending on the country). Therefore, refurbishment of existing buildings can bring significant energy savings. It is also true for the Czech Republic, where the average age of houses with multiple flats is 52 years, and that of family houses is 49 years. Reducing the building energy performance can also bring other economic, social, and environmental benefits. It has an indisputable impact on the availability of heating and cooling-approximately 16% of the population live in energy poverty just in the Czech Republic. Investing in reducing the building energy performance also stimulates the economy, especially the construction sector, which accounts for around 9% of European GDP and directly employs 18 million people. The term \"Energy Performance of Buildings\" (EPB) of 2018/844/EU is defined as follows: The energy performance of a building shall be determined on the basis of calculated or actual energy use and shall reflect typical energy use for space heating, space cooling, domestic hot water, ventilation, built-in lighting, and other technical building systems. The energy performance of a building shall be expressed by a numeric indicator of primary energy use in kWh/(m\({}^{2}\).y) for the purpose of both energy performance certification and compliance with minimum energy performance requirements. The methodology applied to determine the energy performance of a building shall be transparent and open to innovation. The amendments to Directive 201/31/EU clarify and add some terms in the definitions and interpretation of terms section.