Edmundas Monstvilas’s research while affiliated with Kaunas University of Technology and other places

The article presents an analysis of changes in energy efficiency of new office buildings designed and constructed during the implementation period of the Energy Performance of Buildings Directive (2014–2024). Common criteria on energy efficiency were collected from Energy Performance Certificates (EPCs) and processed. The changes in final and primary energy for space heating, cooling and hot water production of certified office buildings were determined, and the improvements in buildings, their energy systems and energy sources were analysed. It was determined that buildings of Class C, designed between 2006 and 2017, showed an average thermal energy consumption for heating of 61, for cooling of 13 and for hot water production of 30 kWh/(m2·year), while buildings of Class A++, designed after 2020, consumed, respectively, 6, 9 and 17 kWh/(m2·year). The main reasons for these changes in energy consumption are the significant improvement of thermal insulation, increase of renewable energy in the heat supplied by district heating, the use of heat pumps for cooling, more efficient hot water boilers and optimized and insulated distribution pipelines. Even better results were hindered by the increased area of glazing, insufficient use of solar protection, users’ preference for buildings of complex shape, and technically complicated electricity production. The results revealed that EPCs are an appropriate database for the analysis of changes in energy efficiency of buildings and for setting tasks for further improvement.

One of priorities of the EU’s climate change policy is the energy performance of buildings. This is reflected primarily through the series of Directives the EU has enacted along the years, but is most precisely conveyed in the Energy Performance of Buildings Directive (EPBD). As part of the European Union, Lithuania has enacted its own long-term strategy aimed at transforming the current building stock in one which is more energy efficient. Building energy certification, legalized in accordance with the requirements of the directive is the primary tool used to evaluate the energy-efficiency of a building, which includes determination of the energy consumption of a building and subsequently assigning it with an energy performance class. Energy performance certificates (EPC) are obligatory for new and existing buildings in all European Union (EU) member states and provide not only a description of the energy performance characteristics of individual buildings, but are also useful source of legal information for determination of the achievements of building energy efficiency improvement strategy. Despite the current wide spread presence of EPC analyses in other European countries, similar information on the national EPC register of Lithuania is still hardly present in research studies. To this effect this paper presents a detailed overview of the stock of Lithuanian residential 1-2 apartments buildings using data from the national EPC register. The results obtained present the impact of the implementation of EPBD on Lithuanian residential 1-2 apartments buildings, including changes in thermal insulation of building elements, heating system typology, energy consumption and CO 2 emissions.

Currently, the optimization of thermal energy consumption in buildings is considered a suitable alternative in the construction of new buildings, as a result of which the overall energy efficiency of the building increases. Thus, this study examined the efficiency and efficacy of different building renovation packages conducted across several buildings in Latvia and in Lithuania (across a larger building stock). In the first section of this study, 13 multi-apartment residential houses with 3 building renovation packages have been investigated in the city of Daugavpils, Latvia, in order to determine the actual reduction in heat energy consumption across each of the renovation implementation packages. The study findings indicate that changes in Latvian building regulations regarding insulation thickness did not significantly impact thermal energy consumption in fully renovated buildings. However, the combination of facade renovations, upgraded heating systems, and improved ventilation systems resulted in substantial energy savings, with an average reduction of 50.59% in thermal energy consumption for space heating across the reviewed multi-apartment residential building stock. In the following section of this study, the impact of the Energy Performance of Buildings Directive (EPBD) on building energy efficiency in Lithuania has been examined. The results show that over a 10-year period in the 2000s, Lithuanian building stock experienced a 20% increase in energy efficiency, followed by an additional 6.3% increase between 2010 and 2016. The mandatory requirement for renovated buildings to achieve a minimum energy efficiency class has resulted in significant reductions in energy consumption for heating purposes. The findings underscore the effectiveness of building renovation packages and the EPBD regulations in enhancing energy efficiency and promoting sustainable building practices. The importance of heat metering, consideration of indoor air temperature, and the need to address indoor air quality during renovations were also highlighted.

One of priorities of the EU's climate change policy is the energy performance of buildings. This is reflected primarily through the series of Directives the EU has enacted along the years, but is most precisely conveyed in the Energy Performance of Buildings Directive (EPBD). As part of the European Union, Lithuania has enacted its own long-term strategy aimed at transforming the current building stock in one which is more energy efficient. Building energy certification, legalized in accordance with the requirements of the directive is the primary tool used to evaluate the energy-efficiency of a building, which includes determination of the energy consumption of a building and subsequently assigning it with an energy performance class. Energy performance certificates (EPC) are obligatory for new and existing buildings in all European Union (EU) member states and provide not only a description of the energy performance characteristics of individual buildings, but are also useful source of legal information for determination of the achievements of building energy efficiency improvement strategy. Despite the current wide spread presence of EPC analyses in other European countries, similar information on the national EPC register of Lithuania is still hardly present in research studies. To this effect this paper presents a detailed overview of the stock of Lithuanian residential 1-2 apartments buildings using data from the national EPC register. The results obtained present the impact of the implementation of EPBD on Lithuanian residential 1-2 apartments buildings, including changes in thermal insulation of building elements, heating system typology, energy consumption and CO2 emissions. Introduction Over the last few decades, the general trend observed in Europe, driven by a period of relative economic expansion and prosperity has been one where there was an increasing trend towards individuals being able to build an individual space as their own home-a single-or two-family residential house [1]. The quality of these 1-2 apartment buildings is primarily defined by the selection of building structures and materials, and the type and parameters of the equipment installed in them [2]. Driven by concerns on climate change, the energy consumption in buildings has become increasingly important, with various strategies and international agreements being enacted to address this issue. As is to be expected, this is also being addressed at an academic level, with specific studies aimed at looking for the most accurate and advanced methodology to make informed decisions on the design of low carbon housing [2-4]. The primary instrument for improving building energy performance in the EU is the Energy Performance of Buildings Directive (EPBD), which was first introduced in 2002 (EPBD 2002/91/EC) [5] and then subsequently revised in 2010 (EPBD 2010/31/EU) [6], and in 2018 (EPBD 2018/844/EU) [7]. The EPBD, which is the major legislative and policy instrument in the EU, relating to energy-efficiency in buildings

As per general provisions of European Directive 2010/31/EU on the energy efficiency of buildings (recast), the Lithuanian government transposed the Directive into Lithuanian national law. In the process, the Lithuanian government prepared strategic documents in the field of energy performance and renewable energy that were integrated together through the National Energy and Climate Plan for 2021–2030 (NECP). To better understand the current situation vis-à-vis energy performance, the main characteristics of buildings pertaining to the Lithuanian multi-apartment building stock, classified according to their energy performance class, are analysed and discussed in this paper. Through the exploitation of data from the national Energy Performance Certificate (EPC) register, an overview of the energy performance of the existing Lithuanian residential building stock is presented along with an analysis of the unused potential energy savings pertinent to this building category. The results obtained from the analysed data of energy consumption in buildings shows that the policies adopted over the years were successful in improving the building stock, promoting the move towards the specifications required by a Class A++ (nearly zero energy buildings—NZEB) by 2021. The results show that this was primarily achieved by a significant reduction in the thermal energy used for space heating.

Energy performance certificates (EPC) are obligatory for new and existing buildings in all European Union (EU) Member states, and provide not only the characteristics of individual buildings but are also useful for energy management and planning. However, despite the current widespread of EPC analyses in other European countries, the information of national EPC cadastre in Lithuania is hardly adapted in research studies. This paper presents an overview of the energy performance of Lithuanian residential building stock using data from the national EPC register. The results determine the current situation in Lithuanian residential buildings emphasizing CO2 emissions and their dependencies on different heating systems during latter 5 years. The findings of this research could be used as guidance for management of CO2 emissions in order to comply with the EU requirements by 2050. Moreover, the recommendations for the extended scope of national EPC content are also proposed.

Construction sector accounts for 40 % of the total energy consumption in Europe and produce about 35 % of all greenhouse gas emissions. Residential buildings that represent almost 66 % of the energy consumption and more than 64 % of the emissions of the total building construction sector are the vast majority of the building sector and play a significant role in the energy and environmental footprint of the whole building stock. Energy performance certificates (EPCs) of buildings that are obligatory for new and existing buildings in all European Union (EU) Member states when they are being constructed, sold or rented not only provide the characteristics of individual buildings, so stimulating the real estate market towards better energy performance, but are also useful for energy management and planning in the building sector. However, despite the current wide spread of EPCs related analyses in other European countries, the information potential of this national cadastre in Lithuania is nearly not adapted in research studies at all. This paper presents an overview of the energy performance of the existing Lithuanian residential building stock by exploiting data from the national EPCs register. The results determine the current situation in Lithuanian residential buildings emphasizing CO2 emissions and their dependencies with different thermal sources that are used to generate the operational energy during latter 5 years. The findings of this research could be used as guidance for management of CO2 emissions in order to comply with the EU requirements to meet ambitious climate and energy targets for 2020 by promoting a greater use of renewable energy sources. Moreover, the recommendations for the extended scope of national energy performance certificates’ content were also proposed.

It is necessary to evaluate primary energy consumption from renewable energy resources in energy efficient buildings in accordance with the requirements of the European Parliament and Council Directive 2010/31/EC "Energy performance of buildings". The problem is that in different EU countries, there are no unified methods that evaluate primary energy factor values of photovoltaics. Another problem is that there are various calculation methods, which are lack of clear description, and the results of these methods are inaccurate. In this paper a comparison of different methods for the evaluation of primary energy factor values of photovoltaics are given and as a case study the case of Lithuania was chosen. The comparison showed that empirical value of primary energy factor for photovoltaics is much smaller than that currently used in the EU standard.

It is necessary to evaluate primary energy consumption from renewable energy resources in energy efficient buildings in accordance with the requirements of the European Parliament and Council Directive 2010/31/EC " Energy performance of buildings ". The problem is that in different EU countries, there are no unified methods that evaluate primary energy factor values of photovoltaics. Another problem is that there are various calculation methods, which are lack of clear description, and the results of these methods are inaccurate. In this paper a comparison of different methods for the evaluation of primary energy factor values of photovoltaics are given and as a case study the case of Lithuania was chosen. The comparison showed that empirical value of primary energy factor for photovoltaics is much smaller than that currently used in the EU standard.

Heat pumps are widely used in buildings due to high energy performance and environmental-friendliness. 2010/31/EU Directive of the European Parliament and Council requires assessing the consumption of primary energy generated from renewable sources when calculating the energy performance of buildings. However, the equation given in the 2009/28/EU Directive and guidelines 2013/114/EU of the European Commission does not take into account the amount of energy supplied by electric heat pumps into buildings. The paper presents the method that does not assess the energy input of primary sources for transforming electric power and for this reason, the calculations result in a lesser amount of energy than the ones obtained by the method of 2013/114/EU Directive. The calculation results proved that using merely heat pumps in nearly zero-energy buildings will not ensure the necessary amount of energy from renewable primary energy sources. Hence, to ensure the lacking amount of energy other renewable energy sources, such as solar panels, wind power plants, hydro power plants, biofuel, etc. are necessary to use. DOI: http://dx.doi.org/10.5755/j01.sace.11.2.9986