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Zero Energy Buildings and Thermal Insulation

Released by Turkey's Ministry of Energy and Natural Resources, Energy Balance according to the report; Energy consumption in 2018 was approximately 108.5 million TOE. In our country, as in the EU, the amount of energy consumed in buildings has a significant share in the total consumption. According to 2018 data, 30.5% of energy is consumed in buildings in our country. Most of the energy in the EU is provided from outside the union. 74% of our energy need in our country is supplied from abroad. Although energy imports decreased by 4.2% in 2019 compared to the previous year, it was over $ 41 billion. Foreign dependency in energy causes problems related to energy security.

On the other hand, but not so ambitious EU together with Turkey's declared intention to contribute up to 21% are national emission reduction commitments. Since fossil fuels are predominantly used in our country, the increase in energy consumption also brings about an increase in greenhouse gas emissions. Turkey's greenhouse gases increased by 140.1% compared to 1990 levels in 2017 reached 526.3 million to tone levels.

Today, developed countries have turned to concepts such as zero-energy houses and passive houses. The EU Directive on the energy performance of buildings was adopted in 2002 which intended to improve the energy efficiency of buildings, reduce carbon emissions and reduce the impact of climate change.

recast directive 2010/31/EU was adopted on 19 May 2010 to strengthen energy performance requirements and to clarify and streamline some of the provisions from the 2002/91/EC Directive.

Buildings sector, account for 40% of total energy consumption in the European Union. In order to reduce the Union’s energy dependency and to honour its commitment to reduce overall greenhouse gas emissions by at least 20% below 1990 levels by 2020, it is necessary to reduce energy consumption in the building sector and to increase the proportion of energy from renewable sources. This approach will also help improve energy security strategies of the Union.

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A number of measures are set out to help achieve these objectives in Energy Performance of Buildings Directive. Article 9 of the Directive requires member states ensure that:


It requires that member states draw up national plans for increasing the number of nearly zero-energy buildings and develop policies and take measures to stimulate the transformation of buildings that are refurbished into nearly zero-energy building.


Article 2 of the Directive defines a nearly zero-energy building as ‘…a building that has a very high energy performance and the nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources,  including energy from renewable sources produced on-site or nearby.’


However, it does not define a specific standard of performance that might be considered ‘nearly zero’ and instead, says that national plans should include, detailed application in practice of the definition of nearly zero-energy buildings, reflecting their national, regional or local conditions, and including a numerical indicator of primary energy use expressed in kWh/m2 per year


In total, 17 examples of educational buildings have been defined and compared, of which three are kindergartens, eight are schools (mostly primary schools), two are combined kindergartens and schools, and four are university buildings in 13 different countries. The main results of the comparison related with building envelope and U values are [1]:


Concrete/masonry construction was the most used, although several of the buildings are of lightweight construction. The windows are triple-glazed in ten of the buildings and double-glazed in four of the buildings. U-values were found within the following ranges:

  • Walls: 0.09 – 0.40 W/m²K (average: 0.16 W/m²K)

  • Windows: 0.60 – 1.76 W/m²K (average: 0.97 W/m²K)

  • Roof: 0.06 – 0.30 W/m²K (average: 0.13 W/m²K)

  • Ground/cellar ceiling: 0.06 – 0.56 W/m²K (average: 0.19 W/m²K)


[1] NZEB-like Educational Buildings- Pilot projects from 13 countries Authors: Hans Erhorn, Heike Erhorn-Kluttig,


Insulation is one of the most important parameters in reducing energy consumption, which is the basic principle of nZEB buildings. The U values ​​provided in many projects and the above can only be achieved with high insulation performance. To decrease the U values, the insulation thicknesses should be increased.


All reports, explanations, statistics and studies reveal that energy efficiency in buildings is a very priority issue. Approximately 80% of the energy used in residences is consumed for heating and cooling purposes. Therefore, "thermal insulation" is a precaution that all developed countries frequently and primarily apply with the efficiency of 50-60%. It is possible to reduce the total energy bill of our country by approximately 15 percent by using thermal insulation to be applied on the roofs, walls, floors of all new buildings and coated insulating glass units on windows. In Turkey, only by making energy efficient buildings (at least class C buildings) $ 9 billion savings can be achieved every year.


As a result; Turkey’s and EU 's problems are very similar. However, considering the applications made to solve the problems, it can be stated that although the energy resources of our country are limited, the necessary steps regarding energy efficiency are not taken quickly enough.


2002/91 / EC on the harmonization of Building Energy Performance Regulations was published in Turkey in 2008. On the other hand the 2018/844 / EU, which has been focused on the measures to be taken in the existing buildings with the revision of the EU / 2002/91 / EC in 2010 and with the definition of nZEB (2010/31 / EU), has not been harmonized yet. In our country, U values should be improved and brought to EU level as soon as possible, and nZEB definition should be made, and encouraged by state policies.

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