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Energy efficiency: sustainable building is not economical?

energy efficiency

Energy efficiency is essential. The fact is that around 40 percent of the total energy consumption goes to the building sector, which is also the biggest CO2 and energy saving potential. In the area of ​​Austrian households, space heating accounts for almost 73,3 percent of final energy consumption in the amount of 272,5 Petajoule (Energy Status Austria). Whoever thinks that energy consumption in domestic households is falling due to crisis and environmental awareness is wrong: the climate-adjusted final energy consumption ever Inhabitants (Note: In order to level the weather-related fluctuations in final energy demand, an environmental adjustment of energy consumption is necessary.) Rose to the year 2008, 2009 fell sharply due to the economic crisis and then stagnated. Since 2012, it has risen again and was around 2013 percent higher in 26 than in 1995.

Apartments in need of renovation

In particular, the existing building stock has a lot of catching up to do in terms of energy efficiency and economy. 2,2 million homes or around 60 percent of the total housing stock would need energy-efficient refurbishment ("Efficiency Potentials in Austrian Housing Policy", IIBW 2012). The refurbishment rate in Austria has been around one percent for decades, meaning that it takes 100 years until the building stock is completely renovated. In addition, the thermal renovations make up only part of the total renovation. Energy is literally thrown out of the window.

Economic damage

The fact that sustainable construction and renovation is not only an economic aspect of every household, but also an economic factor is not later than the introduction of the reorganization check of the Federal: 2013 could be supported with 132,2 million euros in funding sustainable investment of 847 million euros. In total, 12.715 jobs were secured or created and 3,6 saved millions of tons of CO2 emissions.
This is contrasted by the study "COIN - Cost of Inaction: Assessing the Costs of Climate Change for Austria", according to which Austria's economy has to cope with up to 2050 billion euros of damage caused by climate change every year until 8,8 becomes.

Key energy efficiency

Which building types and which building materials are the most economical? - This question has been investigated, inter alia, the current study "Innovative building concepts in the ecological and economic comparison over the life cycle". The conclusion: "Since the energy consumption from building use causes a significant proportion of the environmental impact of buildings, the main focus must be on the planning and design of buildings. Comprehensive overall concepts are also important today for small properties such as single-family homes. "And:" First and foremost in the catalog of measures must continue to be increasing the overall energy efficiency of buildings. "

Running costs substantially

Even if the result of the study does not speak clearly for one or more variants of the building, a substantial conclusion can be reached, according to the study authors: "The only blessing and the world saving building concept does not exist. The mere consideration of the initial investment of a building, ie excluding the construction costs (manufacturing costs), never creates a correct picture of the true cost of a building. Although lifecycle cost accounting is based on a variety of assumptions, the project clearly demonstrates that here, too, the total cost over the estimated useful life (50 years) is very much influenced by the ongoing costs of using the building. "

Decisive factor energy prices

However, the study has two drawbacks: only the current energy prices were used for the calculations, so future price increases are not taken into account. In addition, very high production costs were calculated, which - proven by other studies - can now be undercut.
Since higher energy prices of every kind are to be expected in the coming decades, building concepts with a focus on energy efficiency - ie passive houses as well as zero and plus energy houses - clearly have the advantage here. The bottom line is that these concepts are also cheaper in the overall cost balance, if they do not even emerge as a winner in comparison. Any additional costs are put into perspective, to what extent is not predictable due to the energy price development.
"Fact is: without energy efficiency, there is no sustainable building. It is no longer about whether climate change is taking place, but only about how strong or unfavorable the consequences are. If you want to save CO2, you build and operate your houses energy-efficiently and with the most advantageous use of renewable energies in the provision of residual energy requirements. Anyone who claims to the contrary opts for those who are not very interested in the medium-term future and who may be more likely to look at a favorable present from an economic point of view, "says Robert Lechner, Austrian Ecology Institute ÖÖI.

Energy prices

A key factor in considering the economics of sustainable construction and rehabilitation is energy prices - especially those for crude oil. Apart from the fact that fossil fuels are limited and run out in unknown but foreseeable time, the last years have shown the unpredictability of the price development. One thing is certain: the prices of fossil fuels will continue to increase in the long term.
The Federal Ministry of Science, Research and Economy in the Energy Status Report 2015: "In the longer term, the crude oil price (adjusted for inflation) 2003 / 04 has again reached the level at the beginning of the 1990er years and then increased so much that he in the year 2008 the values 1980, the highlights of the 2. Oil crisis, far exceeded. In the last few months of 2008, a price plummet set in and 2009 was the real oil price at around. 60 dollar / barrel, which is about the level of the year 1982. In the years 2010 and 2011 the price rose again strongly and reached recently with approx. 102 dollar / barrel a record. In 2012, the price was just below 100 dollars / barrel, nearly three times the price of 1990. In 2013, it was again slightly down and was recently at around 95 dollar / barrel. The price trend on the international markets has of course strongly influenced the energy price situation in Austria. "
At the beginning of 2015, the price of oil plunged below 50 dollars and most recently around the 60 dollar.

From standard to high tech

One thing is certain: Like every product, a house costs more or less depending on the quality and performance. The lowest category of sustainable construction and therefore also standard construction characterizes the low-energy house, the highest is the plus-energy house, which even yields an energy yield in the overall balance. In between are the building concepts Passive House and Sonnenhaus as well as mixed variants.

Costs dropped

The study of the University of Natural Resources and Applied Life Sciences Vienna "Sustainability monitoring of selected passive house residential buildings in Vienna" has compared the production costs compared to the building standard low-energy house. The result: the costs of sustainable construction are falling due to technical developments, at least in multi-storey residential construction. The authors: "The additional costs of the first Viennese passive house residential units were at about 4-12 percent, whereas in the future more cost-efficient decentralized building services systems can rather assume a range of 4-6 percent."
Using the example of the construction of a semi-detached house, the current German study "Price Development of Building Energy Efficiency" has shown how actual costs of 1990 have developed to this day in the light of increasing legal requirements for energy efficiency - price-adjusted via the construction cost index. The result: Numerous components such as cellular concrete walls, windows, roof or heating pumps today cost far less or you get a much better quality for the same price. The authors: "In view of the results of this initial study, the thesis of" increasing energy efficiency as a natural enemy of cost-effective construction "does not seem to be tenable." The study even concludes that both today's new construction standard and all future standards good planning today can already have the lowest monthly costs than the past standards of recent decades.

Economic efficiency calculated

The Energy Institute Vorarlberg and e7 Energy Market Analysis have calculated the future energy costs. In the study "Analysis of the cost-optimal requirements level for new housing construction in Vorarlberg" (2013) different types of buildings and combinations - single-family and multi-family houses, solid and wooden construction, as well as gas, pellet and heat pump heating - in terms of energy efficiency and efficiency over 30 years calculated and compared. The initial investment costs for energy-relevant components and components, planning costs, maintenance and repair costs as well as energy costs including price increases were included.

The basis for the construction costs was the comparatively high Vorarlberg price level. Result: Although the investment costs of the best energy variants with solar system compared to the variants according to standard low energy and without solar system are higher, but the actual cost-effectiveness is reflected in the consideration over several decades.
These studies by different authors clearly show that the additional costs for optimally ecological and energy-efficient buildings are equalized over decades or are extremely low.

Heat loss & savings potential

A calculation, which saving by refurbishment is possible, the research institute for heat protection FIW in Munich in a study employed. As an example, a single-family home in the age group 1968 to 1979 served (incl. Fluctuation range). If the total refurbishment costs are calculated according to the example of 67.780 Euro, the savings result in an additional cost / benefit ratio of 2,28 Euro / kWh a and a mean payback period of about 16 years.

graphic waermeverlust
Relative proportions of the individual components and the ventilation heat losses on the total heat losses for a typical refurbished and renovated detached house of the building age class 1968 to 1979. Energy is literally thrown out the window: In general, the following key is assumed for the significance of the individual components for energy efficiency (the percentages vary somewhat according to the opinion): The heat loss in non-energy-efficient buildings lies in the construction (walls, roofs and roofs) Floor) at about 50 percent, at the windows at about 30 percent and by venting at about 20 percent. The research institute for heat protection FIW in Munich wanted to know it exactly in the study "economy of heat-insulating measures" and calculated the shares of the heat losses with existing buildings as follows: wall 30 percent, roof 20 percent, cellar 12 percent, window 16 percent, thermal bridges 6 percent (also particularly relevant in the window) as well as vent 14 percent. Interestingly, the more energy-efficient a building is, the more important the factor becomes, ie the user behavior or the use of heat recovery.

The optimal insulation thickness

New results on the optimal dam strength is provided by an online calculator of the Institute for Building Biology and Ecology (IBO). "Time and again in the media is made in a not very factual way against thermal insulation: Expensive, only for the insulation industry advantageous, inefficient, harmful to the environment, problematic in the disposal. baubook has developed an ecological amortization and cost-effectiveness calculator for components, with which it is possible to check transparently whether an insulation measure is profitable and how it affects the environment, "recently presented Bernhard Lipp, Austrian Institute for Building Biology and Ecology (IBO) , the AWR tool (www.baubook.at/awr). With this tool, ecological and economic amortization of insulation measures can be calculated quickly and transparently online. This also brought optimal values ​​to light: Economically speaking, the ideal value lies between 25 and 50 centimeters. An example: For mineral thermal insulation boards, the more accurate optimum values ​​are at least 85 centimeters (ecological) for non-renewable primary energy and 23 centimeters (economic). Nevertheless, it is important to future-proof and energy-efficient to renovate, since it can be assumed that over the life cycle of a building is usually rehabilitated only once.

Photo / Video: Shutterstock.

Written by Helmut Melzer

As a long-time journalist, I asked myself what would actually make sense from a journalistic point of view. You can see my answer here: Option. Showing alternatives in an idealistic way - for positive developments in our society.
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  1. I consider ecological materials to be very important, especially when it comes to insulation. At some point, the insulation panels have to be disposed of ...

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