What kind of heat loss requirements NZEB and deep renovation sets for building envelope?

In most of countries the energy performance of buildings is defined as (primary) energy use of whole buildingâ s (heating, cooling, ventilation, DHW, lighting, HVAC auxiliary, appliances), not as specific requirements for building envelope. For construction companies of production of modular renovation panels it in necessary to know heat loss properties of building envelope (U, W/(m2â K); ï , W/(mâ K); ï £, W/K; q50, m3/(hâ m2)). In this study it is analyzed what kind of heat loss requirements exists for building envelope to meet on annual basis to following targets: nZEB i.e. national nearly zero energy definition; deep energy renovation with 80 % reduction of primary energy; ZEB i.e. net Zero Energy Building = the annual primary energy use = 0 kWh/(m² a). Indoor climate and energy calculations were made based on national energy calculation methodologies in six countries: Denmark, Estonia, Latvia, Czech Republic, Portugal, and Netherlands. Requirements for heat loss of building envelope vary depending on requirements on indoor climate and energy performance in specific country, outdoor climate, availability of renewable energy, and building typology. The thermal transmittance of the modular wall panels for nZEB was â 5% from pre renovation thermal transmittance in Latvia, â 10% in Estonia and up to 50% in Portugal. For roof the decrease of thermal transmittance was smaller mainly due to smaller thermal transmittance before renovation. Results show the difficulties to reach ZEB with multi-story apartment buildings in cold climate. There are not enough places to install renewables for energy production on site.The study has been conducted in the projects H2020 MoreConnect, TK146 the Estonian Centre of Excellence in Zero Energy and Resource Efficient Smart Buildings and Districts, ZEBE, IUT1−15 Nearly-zero energy solutions and their implementation on deep renovation of buildings

1248 Attitude towards LCA in Hungary and Czechia – Results of a survey among building design professionals

Architects and designers have a critical role in promoting Life Cycle Assessment (LCA), a scientific methodology for evaluating the environmental impacts of buildings that can help decarbonise the built environment and minimise other negative effects.This paper presents the results of an international survey conducted among design professionals as part of the IEA Annex 72 project about assessing life cycle related environmental impacts caused by buildings. Twenty-three countries were participating in the survey altogether, but in this paper, only the specific situation in two Central European countries, Hungary and Czechia, are presented. The questionnaire explored the designers’ understanding of environmental problems and LCA methodology, the drivers and barriers of environmental assessment and the future perspectives.The results show that many architects and designers are concerned about environmental problems and the built environment’s contribution but have a limited understanding of the applicable scientific methods. A full LCA is seldomly applied as neither regulations nor clients demand it, and only the operational energy is mandatorily assessed. Further improvements in data quality and assessment tools and regulatory and other drivers are needed to increase the use of LCA in the construction sector