The European Union has set the ambitious aim of reducing human greenhouse-gas emissions by 80-95% by 2050 in comparison to 1990. The EU is slowly moving towards nearly zero-efficiency buildings that in turn create a demand for building materials, as the energy costs of a building make up roughly 40% of total energy usage.
“It is clear that in order to contribute to reducing greenhouse gas emissions, the amount of energy used in a building for heating, cooling, water heating and lighting must be reduced, and renewable energy sources will probably need to be harnessed,” according to Kuldar Kongo, product manager of Krimelte OÜ, in responding to the Energy Performance of Buildings Directive.
All new buildings finished after 31 December 2020 must be nearly zero-energy buildings, according to the aforementioned directive. This requirement for new buildings used and owned by government offices has already been in effect since 2019.
According to Kongo, the energy efficiency of a building depends on the general need for energy, type of supplied energy, on-site production of energy from renewable energy sources, and the amount of heat loss through the outer envelope. “Various methods and solutions must be applied together to meet the requirements of a nearly zero-efficiency building, from the right planning of the buildings’ placement and use of renewable energy sources to well thought-out envelopes to minimise heat loss. The construction of nearly zero-efficient buildings in Europe increases expectations and demands regarding the quality of materials and the competence of salespersons.”
The manufacturers of building materials have been focusing on the development of materials for the construction of nearly zero-energy buildings for years. “For example, the product portfolio of our trademark Penosil includes products that solve technical heat and moisture related issues, thereby contributing to better energy efficiency, and these features must also be kept in mind during any further product development. We have developed a complete solution for energy efficient window placement, by which our products help to solve problems and issues related to a window node. In addition to energy efficiency, the development of our products also considers their durability in time and the contribution to a healthy indoor climate.”
Heat loss through envelope
Increasing the thickness of the insulation layer on the outer envelope is sufficient to minimise heat loss. According to Kongo, it should not be forgotten that although heat loss by conduction through envelopes is one of the major factors influencing energy loss, a building will also lose heat in addition to heat conduction through unplanned air leaks and cold bridges. The insulation layer thickness has often reached its limits of cost effectiveness, meaning that no additions will be cost efficient and one should focus on the removal of air leaks and cold bridges.
“The importance of air tightness is illustrated by the fact that proofing subsequent to construction has become unavoidable”, Kongo adds. “The envelopes are accompanied by a large amount of other important requirements: avoidance of technical humidity issues, fulfilment of indoor climate requirements, reduction of noise issues and fire safety.” He adds that one of the major challenges regarding the buildings is correct window placement, because this involves interruption of the external insulation layer along with the airtight and water vapour proof layers.
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*Article from the journal Inseneeria 02/2019 by Gerli Ramler