Despite some stubborn skeptics, there is now worldwide consensus in research: 11.944 international studies from the years 1991 to 2011 were analyzed by a science team led by John Cook, the result of the "Environmental Research Letters" presented: A total of 97,1 percent of investigations, who comment on it, find that man causes climate change. Incidentally, there is no doubt that climate change is taking place. Recent surveys also show that climate change has also hit the minds of the Austrians: around 45 percent are worried about the climate (Statista, 2015), 63 percent even think that more should be done to combat climate change (IMAS, 2014). The consequences: According to the Climate Change Assessment Report of the Austrian Panel on Climate Change (APCC, 2014), a temperature increase of at least 3,5 degrees Celsius is expected by the end of the century - with enormous ecological and economic effects.
It is also undisputed that buildings are the main cause of greenhouse gases and therefore also of climate change. Around 40 percent of the total energy consumption goes to the account of the building sector, which therefore also represents the largest CO2 and energy saving potential. Austria and the EU have therefore taken numerous measures to counteract climate change. The goal is the transformation to a low-emission, energy-saving society.
Sustainable building - the myths:
Myth 1 - Energy efficiency is not - or is it?
The fact that sustainable, energy-efficient construction and renovation, in particular thermal insulation, has an effect on buildings and how this happens has been precisely calculated and measured at building physics institutes several decades ago. All serious studies and investigations on existing buildings as well as thousands of energy-efficient buildings prove this.
But will the planned, calculated energy savings also be achieved in practice? This question was raised, among other things, by a study by the German energy agency dena 2013, which examined data from a total of 63 thermally renovated buildings over several years. The result is impressive: with a calculated final energy consumption of 223 kWh / (m2a) on average before the refurbishment and a projected demand for 45 kWh / (m2a) on average after the refurbishment, the aim was to save 80 percent energy. After the actual refurbishment, an energy consumption index of 54 kWh / (m2a) and an average energy saving of 76 percent were reached on average.
The result was negatively influenced by a few individual cases that missed the refurbishment target significantly. Unfortunately, this also happens: The first prerequisite for the functioning of energy-efficient measures in new buildings and in refurbishment is a technically correct implementation. Again and again, however, the execution leads to errors that cause the savings effect is less than predicted. The user behavior can also have a negative effect on the expected energy efficiency. Old habits, such as long ventilation or switching off the ventilation of the living space, have a counterproductive effect and must first be discarded.
Myth 2 - Energy efficiency does not pay off - or does it?
The question of whether the additional costs for sustainable construction and renovation also pay off financially has also been positively answered several times by studies and investigations. In particular, it is important to consider the life of a building and the evolution of energy costs.
In principle, all measures are, to a certain extent, economical, but to what extent do the framework conditions and implemented measures decide. Especially worthwhile is a thermal insulation of an old house, the facade would have to be rehabilitated anyway.
However, general statements on cost effectiveness should be considered with caution, since the conditions - amount of investment, construction or building substance, type of heating etc - are not comparable and future energy prices are hard to guess. Apart from the ecological factor, however, aspects such as increasing the value of the property and significantly increasing well-being are also a clear advantage.
Myth 3 - insulation leads to mold - or not?
It is true that in all utility buildings, whether insulated or not insulated, moisture is generated which in some way has to be released outside. Mold is also formed in new buildings, which are not completely dried up after the construction, and especially in buildings in need of renovation. An external thermal insulation - assuming a professional planning and implementation of the structural measures - reduces the heat losses to the outside very strong, thus increasing the surface temperatures of the inner walls. This significantly reduces the risk of mold growth. Often mold growth is also due to the user behavior: Especially with new, denser windows, it is important to observe the air humidity content and to ventilate accordingly or to use an existing living room ventilation system.
Myth 4 - dams is carcinogenic - or not?
Radon exposure and associated cancer risk are often attributed to insulation. However, it is correct that the radioactive radiation caused by the noble gas radon (measuring unit Bequerel Bq) is not caused by insulation, but escapes from the ground into the air due to natural occurrences.
However, radon concentrations are also observed in closed buildings, as the gas can accumulate here. Already increased ventilation of the room or a living room ventilation brings in the normal case a sufficient effect.
Protection can provide, for example, a seal of the cellar against the earth and the corresponding living spaces.
A good overview offers the radon map.
Myth 5 - insulating materials are the hazardous waste of the future - or not?
In particular, thermal insulation composite systems (ETICS) are sometimes skeptically observed with regard to service life and disposal. Their durability is now estimated to be around 50 years: First ETICS were relocated to 1957 in Berlin and are still in working order. Nevertheless, it is clear that thermal insulation must be replaced after a few decades. Ideally, insulation would be reused, or at least recycled.
Reuse is not possible at least in ETICS due to the adhesion to the facade according to the current state of the art. Even if there are first considerations about ETICS with built-in predetermined breaking points, which would facilitate a dismantling, disassembly nevertheless leads in any case to a substantial destruction of the material. However, some companies are already working on solutions such as milling. For other materials such as bulk insulating materials, a reduction of up to 100 percent is possible for reuse.
The recycling of insulating materials is not a technical problem, but is rarely used in practice. For example, the waste can be easily crushed when mounting plate-shaped materials made of hard foam and the resulting granules are used for further use. With EPS, for example, up to eight percent recycled EPS can be fed into production. In addition, there is the possibility of using loose granules as a leveling compound. In addition to the material recycling possibilities mentioned above, there is also the possibility of recovering the raw materials used. If all possibilities are exhausted, the last step is thermal recycling.
Myth 6 - insulating materials contain oil and are harmful to the environment?
The answer to this question lies in the energy and environmental balance sheet (graph). Depending on the insulation material and insulation efficiency, these differ in different ways. The question of whether the use of dams is ecologically worthwhile, but can be clearly affirmed. For example, the Karlsruhe Institute of Technology has compared the resource utilization of insulating materials over the entire life cycle and the positive impact on the environment.
The conclusion: the energetic and ecological payback period of a use of insulating materials is well below two years, thermal insulation is very sensible from the point of view of a primary energy and climate gas balance. Say: not to dam is harmful to the environment.
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