The claim that the better the thermal insulation of the perimeter walls, the greater the energy savings for heating, is not true. This was confirmed by a study that the Association of Masonry Materials Manufacturers commissioned experts on the efficiency of buildings and heating systems to prepare. The study showed that a brick family house with perimeter walls built from single-layer masonry is efficient and energy-saving even with a several-fold increase in energy prices. Increasing the thermal insulation properties of the wall above a certain limit is practically useless.
An expert study showed that the construction of a family house with a perimeter wall, which has a value of the heat transfer coefficient of the structure below 0.16 W/(m².K), is effective even after several times the price of energy. “The basic setting of the standard, which determines our minimum requirements for perimeter structures, is from 2019, i.e. before the period of significant increase in energy prices,” said the chairman of the association, Martin Mihál.
A five-fold increase in prices would be liquidating
According to him, a fivefold increase in energy prices is unlikely and would be devastating for Slovak residents. “The study showed that even with such an increase in energy prices, the current recommendation of the standard is sufficient,” Mihál pointed out. As he noted, walls with a thickness of 500 millimeters built from masonry materials achieve such a value even without insulation. “This means that further increasing the insulation of modern masonry walls, and thereby increasing costs, is ineffective,” added the president of the association to the results of the study.
The study points not only to the correctness of the set standards, but also to the quality of the masonry materials. “The study calculated the life of the house for 30 years, while we know that the life of brick buildings is more than three times longer,” explained the vice-president of the association, Gabriel Szöllösi.
According to him, technologies for the production of masonry materials are constantly evolving, while the study shows that they are suitable even with an extraordinary increase in energy prices. “And even without increased insulation and with minimal heat leakage through building structures,” says Szöllösi.
The result of the study is five different scenarios, in which it compared different insulation thicknesses at different energy prices over 30 years. The calculation of global costs includes the net present value of costs incurred in the specified calculation period, which includes investment costs in the first year, energy costs, maintenance and replacement of elements if their useful life ends during this period. It also includes a discount rate of four percent, an increase in energy prices by two percent per year and the cost of carbon dioxide emissions from 2027, when the upcoming regulation on payment for carbon dioxide production should enter into force.
The considered house in the study was L-shaped
The study was prepared by Jana Bendžalová, executive director of ENBEE, an expert on the efficiency of buildings at the pan-European level, and Laurent Socal, who deals with heating systems and building energy calculation methodologies for the European Commission. They assessed a family house typical of the Slovak environment, which in recent years has been a bungalow. In this case, an L-shaped five-room.
According to the Association of Manufacturers of Masonry Materials, they chose the more complex shape of the building on purpose, since the more complex the shape, the larger the cooled area and the lower the efficiency of the building. As a perimeter wall, there was a fictitious masonry perimeter wall with a thickness of 300 millimeters with an average price and thermal resistance averaged from several manufacturers of masonry materials. The different parameters of the individual variants were achieved by additional thermal insulation.
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