This research was carried out to start the discussion on the amount of harmful emissions that are emitted in producing building and insulation materials for roof constructions. Usually, for the improvement of energy efficiency of buildings and reduction of the embodied thermal energy, effective thermal insulation solutions for the external building envelope have to be provided. From the buildings available for the analysis, in Latvia there were selected multi-apartment buildings of separate series with a uniform composition of roof constructions. Within the context of renovation works, the reports of energy audit for the buildings contain recommendations referred to improvement of the thermal performance of roofs. Using mutually comparable energy efficiency report data, there was drawn up an averaged model of a five-storey multi-apartment residential house. There were taken into account legislative documents relating to thermal engineering of buildings: LBN 002-01 ‘Heat engineering of building boundary constructions’ and LVS EN ISO 6946: 2007 ‘Building components and building elements – Thermal resistance and thermal transmittance’, and moisture regime according to LVS EN ISO 13788: 2001 ‘Hygrothermal performance of building components and building elements – internal surface temperature to avoid critical surface humidity and interspatial condensation – calculation methods’, which states that the roof constructions should be free from possibility of water vapour condensation. In this study, there were calculated energy savings obtained by improving thermal resistance of the roof constructions and the opposite primary energy consumption for the production of building materials. As a result, there is obtained environmentally friendly roof construction.

This paper provides an overview of recent progress reached in semi-transparent photovoltaic systems (STPV), which are being assessed as a potential solution to enhance the productivity of plant grown in greenhouses. Utilizing this kind of renewable energy resources, relating with plant growing is attractive solution to increase sustainability for citizens. The aim of this study is to find out recent advances for application of various semi-transparent photovoltaic systems which can be integrated in greenhouses. Solar PVs are among dependable, mature and cost-effective renewable energy systems and solutions, which are promising for building integrated photovoltaics (BIPV) application. The main emerging photovoltaic candidates for BIPV are amorphous silicon, kesterite, chalcopyrite, CdTe, dye-sensitized, organic and perovskite based systems. A monographic study approach has been utilized in this investigation, in ordain to compile and analyse the photovoltaic systems for BIPV mainly investigating and comparing two main parameters: average visible transmittance (AVT) and power conversion efficiency (PCE). The rapid development of new materials and structures for the manufacture of semi-transparent solar panels allows a balance to be struck between AVT, PCE and a comparison of the reviewed materials indicates that organic and perovskite are the most promising for semi-transparent solar panel production and application in greenhouse constructions, based on their PCE and AVT results.

Newly constructed buildings are subject to stricter requirements – the building must not harm the environment, they must be energetically and economically efficient, comfortable, ecological, etc. One such green energy-saving idea is green roofs and walls of buildings. The purpose of this study is to determine the dynamics of rainwater runoff under real natural conditions, in a typical green roof construction, compared to runoff from a roof covered with bituminous tiles. The study was conducted in the year 2022–2023 by installing two 1 m² stands, which are affected by real climatic conditions. One stand was covered with traditional bituminous tiles, but the other was covered with a ‘green roof’ coating. Meteorological data were obtained from the Kaunas City meteorological station. During the first months of observation, it was possible to record the tendency that rainwater runoff is slow in the case of a green roof, but it continues even after the intense rain has ended. Analyzing the data, it was found during the research that the regression coefficients are very small in assessing the relationship between average daily temperatures and runoff in individual months, R2 – 0.0453 to 0.0553. The study showed that under certain meteorological conditions, a green roof can accumulate up to 35–45 percent more water than a roof covered with bituminous tiles. This means that the water is accumulated and then slowly drains into the rain collection systems.