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.

Actual and reliable meteorological data are necessary for building performance analysis. Since meteorological conditions vary significantly from year to year, there is a need to create a test reference year (TRY), to represent the long-term weather conditions over a year. In this paper TRY data model was generated by analysing every 3-hour weather data for a 30-year period (1984 – 2013) in Liepāja, Latvia, provided by the Latvian Environment Geology and Meteorology Centre (LEGMC). TRY model was generated according to standard LVS EN ISO 15927-4. The generated TRY contains from typical months that are included in TRY from a number of different years. The data gathered from TRY was compared with the climate data from the Latvian Cabinet of Ministers regulation No. 379, Regulations Regarding Latvian Building Code LBN 003-15. Average monthly temperature values in LBN 003-15 were lower than the TRY values that indicate on climate changes in this location. The results of this study may be used in building energy simulations and heating-cooling load calculations for selected region. TRY selection process should include the latest meteorological observations and should be periodically renewed to reflect the long-term climate change.