Sustainable renovation methods in Europe


The aim of the EPS project 2016 was to point out some successful cases where refurbishment of buildings have been done, with a reduction of energy consumption and improvement of living comfort as the result.

These cases are described in more detail and they inform about some techniques which has been used in the building renovations as well as showing costs, work periods, materials, and pictures that demonstrate how some of the tasks were carried out.

Read more about the cases here

Figur 1

What is EPS?

The EPS, also known as the European Project Semester, is a program offered by seventeen European universities in twelve countries throughout Europe, created with engineering students in mind, but other students are also welcome.

The main objective is to train students from different countries and different disciplines to work together in multi-cultural and multi-disciplinary groups. The students work together to execute an integrated engineering-design-and business project.

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1. About EPS

The European Project Semester is a program offered by seventeen European universities in twelve countries throughout Europe, created with engineering students in mind, but other students are also welcome.

Dr. Arvid Andersen was the originator of the EPS concept. He developed the program in Helsingør, Denmark. EPS grew constantly and it is crafted to address the design requirements of the degree and prepare engineering students with all the necessary skills to face the challenges of world economy nowadays. International student teams work on interdisciplinary projects with commercial businesses and industries, selected to match the students’ specializations and capabilities as well as to develop their inter-cultural communication and teamwork skills.

Figure 1: Isologo of EPS

The whole EPS program is composed by different courses and activities, for instance: project management, teambuilding, integration week, Survival Swedish, English lessons, energy week and supporting technical courses.

The main objective is to train students from different countries and different disciplines to work together in multi-cultural and multi-disciplinary groups. The students work together to execute an integrated engineering-design-and business project, focusing on:

  • The development of personal competences, especially the ability to work and communicate within cross-cultural groups.
  • The interrelated work of several disciplines like civil, mechanical & electrical engineering, information technology, business & management, etc.

Team members

The team is formed by five students from different countries of Europe. Our international and intercultural project group consists of Austrian, German, French and Spanish students. Because of the intercultural mix, everyone is used to different working techniques and that can be challenging in some situations. Each of us come from different universities and our field of studies are also mostly different.

The fact that all team members presents different backgrounds, which are in our opinion a positive aspect, which might affect the results of our project positively. To conclude the team was composed by the results obtained at a Belbin test, which gives us an overview about the different personal qualities of each team member.

All team members are represented on the following page with basic information.

Mission and vision

Figure 2: Mission and vision of the project

In these times where the human being is experiencing an important global warming in the climate due to the accumulation of greenhouse gas in the atmosphere, it is extremely important to make aware people of the opportunity which we have to change this situation by the energy reduction in our style of live.

With this project, it pretends to inform of the different existing ways, which are known so far, that reduce this energy consumption in the building sector by the renovation of old buildings in Nordic Countries.

With the purpose to achieve this mission, it has set a series of goals in this project.

  • Gathering enough information and tools in energy efficient and sustainable renovations for buildings.
  • Analyzing of politic from European Union countries with the aim to know the current situation on energy efficiency in Europe.
  • Analyzing of techniques and materials in order to share this information in a simple way with all people, such as companies in the building sector, municipalities, owners, tenants, etc.
  • Searching of successful cases and their subsequent study in order to demonstrate that renovations get their objectives.

Thus, the team hope to contribute to make the world a better place where to live in the future and where our children can enjoy of a healthy and long life in a natural environment.

2. Case studies

The following section aims to show some successful cases in refurbishment of buildings, which are focused on reducing energy consumption and improving the comfort of residents, for the inhabitants.

With the inclusion of these cases, the team want to inform about some techniques which has been used in building renovations, as well as showing costs, work periods, materials, and pictures which demonstrate how to carry out some tasks.

Besides, it is important to stand out that these cases try to prove that the energy consumption can be reduced enormously without spending a lot of money, relocating tenants, etc. providing an increase of quality of living for tenants and also reducing greenhouse gases, something very important nowadays in the politics of European Union countries.

Read more about the cases at:

Contentin Falguière – Paris, France
Apartment block – Oulu, Finland
Brogården Alingsås – Sweden


3. Improve the indoor environment

The indoor environment is becoming more and more important, because the inhabitants of buildings do not like to live under worse conditions after a renovation. And this part is challenging the whole building sector. The new techniques and new materials, which are able to save a lot of energy are not tested well so far. This can be due to the short availability on the market. So, for a successful renovation it is important to use materials and technical equipment which is recommended from building specialists. However, not just the air quality is important to feel comfortable in a building, also acoustic protection should be on a high level, especially in apartments or building which are close to streets with a lot of traffic or other annoying events.

The sustainability and energy saving aspects becomes more important and are been the most of the time implemented into new constructions, therefore the indoor environment quality should not be ignored.

New building becomes air tighter and are also able to save energy, but in the optimized buildings new topics come up which are responsible for a high comfort.

Possible weaknesses of optimized buildings:

  • Less fresh air
  • Overheated in summer
  • Odor pollution
  • Mold/ moister damage

These weaknesses are easy to manage, if the construction is built in a right way.

Guidelines to increase the indoor environment quality

Air quality: Through the targeted and regular entry of fresh outdoor air, the indoor air quality is significantly improved. An hourly outside air intake of 30 m3 per person leads, depending on apartment size and occupancy, an air exchange rate from 0.4 to 0.8 h-1, as already said before. These data are far from being achieved by manual ventilation, so mechanical/comfort ventilation is needed. To improve the air quality it is recommended the installation of filters which leak out air pollution like the high efficiency articulate air filter (HEPA).

Prevent toxic substances: Materials which are available on the market can contain toxic substances, therefore it is important to be sure from which substances these used materials are. The constructor should be especially careful by using new products which are not tested or known, they can consist of toxic substances and have a negative impact on the inhabitants. Substances which are already forbidden are Asbestos, artificial mineral fibers, chlorofluorocarbon (CFC), hydro chlorofluorocarbon (HCFC), polycyclical aromatic hydrocarbon (PAH), polychlorinated biphenyls (PCB) and wood preservative like pentachlorophenol (PCP) and Lindane (hexachlorocyclohexane).Figur 57 draft

Thermal comfort: Comfortable and cozy atmosphere is quite different from person to person, it can be influenced positively or negatively by a variety of factors (e.g. by clothing, acclimatization, color surroundings, air humidity or drafts, etc.). The difference between head and feet in a room should be not higher than 2K to feel cozy and the difference between ambient air and that of the surrounding surfaces of the room should not exceed 2K to 3K. These targets can be achieved with floor heating and well insulated building envelope.

The optimum temperature in a room depends largely on the activity therein. For persons sitting and clad in light clothing, the temperature should not be lower than 20°C and not exceed 23°C (figure 57). In rooms were is more bodily activity than sitting the temperature can be appropriately reduced. Building physics identifies a clearly defined range where human beings feel most comfortable in enclosed rooms – the “optimum comfort range”.

Ventilation: In new constructions it is already standard to implement a ventilation system, but not in renovated buildings. The ventilation system guaranteed fresh air during the whole day and protect the construction of mold, especially after a renovation when the building becomes more air tight it is important to ventilate the rooms. A ventilation system increase the quality of air, with filters it is possible to clean the air before inlet. So the amount of pollen, dust, spores can be reduces significantly and the CO2 concentration can be hold on a constant level which protect from tiredness. A person needs about 30m³/h air by normal activities and for example during sleeping 20-25m³/h, the air supply system is able to deliver exactly the necessary amount of air for each room and this helps also to save energy. And it is also important that the system is silent in rooms where heightened attention is required or where people are sleeping the sound pollution maximum is 25dB (A).

Figur 58 draftLighting: Through various light sanctities, light directions and light colors the daylight effect the people in a different way. From an evolutionary point of view the daylight definite our living rhythmus, so when it is dark people know they have to sleep and when the sun rise a new day begins. Outside the level of illumination is in general high, but the difficulty is to yield the daylight into the rooms.

Sufficient daylight is reached, if the proportion between the area which is light transparent (windows, door, walls, etc.) and the room ground area is minimum 1:10. For rooms where more light is necessary a proportion of 1:5 is recommended. If this goal is not reachable artificial light must be used, therefore it is necessary already in the planning stage to focus on daylight.

To measure the daylight there is a daylight factor which is expressed as a percentage, for standard rooms like bedroom, living room or corridors the daylight factor should be min.2%. For rooms where more light is essential the daylight factor should be min.3%. How to calculate the daylight factor is explained in the following Figure (Figure 58).

Acoustic protection: A powerful noise protection is also necessary for detached houses, and should be observed in the planning stage. Noise can cause health problems, decrease the living comfortability and in the end it is annoying. More about acoustic protection, how to downscale and details under the point acoustic protection in building covers.

4. Materials for renovation

Building material classes – assessment of fire behavior: The distinction of the burning behavior of materials is divided between non-combustible, normally combustible and fire resistant. The classification of building products at a glance:

Building material class Criteria Examples
A1 (non-combstible) Without combustible components Gravel, sand, clay, brick, concrete, steel, cement mortar, glass, building ceramics, calcium silicate boards
With minor combustible ingredients Mineral fiber panels with low resin bond
A2 (non combustible) Incorperating inflatable elements Plasterboard, gypsum, fiber boards, mineral fiber boards with synthetic resin bond
B1 (flame-retardant) Cork, plastics, PS foam, rigid PVC, wood-wool plates
B2 (normal flammability) Roofing felts, wood, PU foam
B3 (highly flammable) Untreated wool, straw, paper, cardboard

Insulation materials

In the following specifications there can be seen the different insulation materials which can be used in the already explained techniques for each part of the building.

SeagrassSeagrass draft

Definition: Seagrass is a natural insulation, which insulates well, it is also difficult to burn and it does not attracts vermin. Seagrass grows extensively in the Baltic Sea and the Mediterranean Sea.

Advantages: Sorption material, which means that it can absorb moisture, even a temporary influence of moisture does not lead to the formation of mold. This fact is because of the high salt content which is up to 2%. This materials requires also no chemical additives.

Disadvantages: Seagrass may be comparatively quite durable, but it should not be used in outdoor applications and it is not suitable for compression.

Methods/Techniques: Combinable with almost every technique.

Application: Walls and floor

Thermal conductivity: 0.037 W/mK

Price range: 30-50€/m2

Cellulose FiberCellulosse fiber draft

Definition: Fibers made with ether or esters of cellulose, which can be obtained from the bark, wood or leaves of plants, or from a plant-based material. Besides cellulose, these fibers are compound of hemicellulose and lignin, and different percentages of these components are responsible for different mechanical properties observed.

Advantages: Diffusible material, resistant against pests and mold, elastically and easily available in big quantities.

Disadvantages: During the installation the material abrades readily, not suitable for compression, not moisture resistant and it swells even slightly on.

Methods/Techniques: Cavity wall insulation and insulation between rafters.

Application: Walls, roof and floor

Thermal conductivity: 0.030 -0.045 W/mK

Price range: 20-30€/m

Sheep WoolSheep wool draft

Definition: Sheep Wool Insulation is environmental friendly, a green way to insulate and partially supporting fibers of polyester. Sheep Wool Insulation acts as a buffer between the cold damp weather outside and the warm dry environment inside.

Advantages: It is a sustainable and a renewable resource. As wool is breathable, it absorbs moisture to keep the house warm during winter, and releases moisture in summer by high temperatures, getting a perfect temperature balancing. This material is very elastic, it presents fine dust particles and a high water absorption capacity.

Disadvantages: This material is not suitable for compression and the flammability of it, is in a normal average (B2).

Methods/Techniques: blowing insulation

Application: Roof

Thermal conductivity: 0.035 -0.045 W/mK

Price range: 25-40€/m2

Mineral wool (Glass wool/Rock wool)Mineral wool draft

Definition: Mineral wool is an insulating material made from fibers arranged using a binder into a texture similar to wool. The process traps many small pockets of air between the glass/rock, and these small air pockets result in high thermal insulation properties.

Advantages: High UV resistant, quite flexible, non-flammable (A1) and resistant against pests as well as to mold and rot.

Disadvantages: Not suitable for compression, it presents high energy costs in the production. Skin irritation are possible during the installation and the firer dust is suspected to be carcinogenic.

Methods/Techniques: Combinable with almost every technique.

Application: Walls, ceiling and roof

Thermal conductivity: 0.030 -0.045 W/mK

Price range: 20-70€/m2

Corkcork draft

Definition: Cork is consist of suberin, ahydrophobic substance and, because of its impermeable, buoyant, elastic, and fire retardant properties, it is used in a variety of products.

Advantages: Renewable resource with a good thermal conductivity, good sound insulation and a high ability of compost. It is also breathable attractive, rotting and rot-resistant and it presents a high suitable for compression.

Disadvantages: The flammability of it is in a normal average (B2) and impregnated cork is not compostable.

Methods/Techniques: Combinable with almost every internal insulation technique.

Application: Walls and floor

Thermal conductivity: 0.045 -0.055 W/mK

Price range: 20-50€/m2

Coconut coirCoconut coir draft

Definition: It is a fibrous material, which is found between the hard internal shell and the outer coat of a coconut. When it is used as an insulation material it is often combined with boron salt or ammonium sulfate as a flame retardant.

Advantages: Permeable, durable, long lasting, pests resistant, break and tear proof as well as moisture proof.

Disadvantages: The flammability of it is in a normal average (B2), it is expensive and this material is not suitable for compression.

Methods/Techniques: Combinable with almost every external insulation technique.

Application: Walls

Thermal conductivity: 0.040 -0.050 W/mK

Price range: 60-90€/m2

StrawStraw draft

Definition: This material is an agricultural by-product, the dry stalks of cereal plants, after the grain and chaff have been removed. For insulation use it is compressed into bales cornstalks combining it with boron salt as fire protection.

Advantages: Permeable, low priced, hardly energy consumption in the production.

Disadvantages: Low flexibility and the flammability of it is in a normal average (B2).

Methods/Techniques: Combinable with almost every technique.

Application: Walls, roof and floor

Thermal conductivity: 0.038 W/mK

Price range: 40-50€/m2

Wood fiberWood fiber draft

Definition: Wood fibers are extracted from wood residues such as wood chips or rinds from sawmills. Wood fibers are treated by combining them with other additives. The insulation in wood can be used both indoors and outdoors of the home almost everywhere, except for the perimeter insulation.

Advantages: This material is diffusion open, it absolves swelling processes from the other materials and the humidity control is one of the best.

Disadvantages: The flammability of it is in a normal average (B2) and the installation is very expensive.

Methods/Techniques: Under cladding and other similar.

Application: Walls, roof and floor

Thermal conductivity: 0.040 – 0.0060 W/mK

Price range: 25-40€/m2

Hemp/FlawHemp draft

Definition: Commonly used term for high-growing industrial varieties of the cannabis plant and its products. Hemp is not to be confused with the close relative cannabis, which is also a cannabis plant, but is widely used as a recreational drug and medicine. Concrete-like blocks made with hemp and lime have been used as an insulating material for construction. Such blocks are not strong enough to be used for structural elements; they must be supported by a brick, wood, or steel frame

Advantages: Permeable, resistant to mold and pests, good soundproofing, flame retardant (B1), untreated hemp fibers are recyclable and environmental friendly.

Disadvantages: This material is not suitable for compression.

Methods/Techniques: Combinable with almost every technique.

Application: Walls, roof and floor.

Thermal conductivity: 0.030 – 0.0045 W/mK

Price range: 15-35€/m2

Foam (EPS)Foam draft

Definition: EPS is a flexible, versatile and economical insulation made of Styrofoam and is referred to as open-cell insulation material made of expanded polystyrene. EPS is most often seen as insulation panels, which are used for the insulation of facades within a heat recycling system (EIFS).

Advantages: Low cost, good thermal insulation properties, simple application/installation, low environmental impact and health burden, moisture resistant and flame retardant (B1).

Disadvantages: Not UV resistant, low flexibility and it can release toxins in case of fire.

Methods/Techniques: Glued doubling and wedge-dowelled

Application: Walls

Thermal conductivity: 0.030 – 0.0045 W/mK

Price range: 15-25€/m2

5. Renovation guide

Improve building cover

The first objective in a building renovation should always be to improve the building cover in order to reduce the heat losses. The thermal building cover consist of outer walls, base plate, basement ceiling, windows, outer doors, ceiling and roof. There are different methodologies which are used to improve the thermal cover. One of the most common technique is to improve the outer walls by upgrading the insulation which is situated on the outside of walls, but there are also other system which can be realized like the indoor insulation or the insulation between to walls. Every technique has its own pros and cons and this should be discussed before the renovation starts well. Another very important aspect in a renovation would be: the windows and doors. Windows are important to be of high quality and not just because of heat loses protection, but also responsible for the solar heat earnings. Regarding roofs and ceilings are also one of the main critical areas, in order to save heat energy, because hot air rise and therefore the insulation should be of high quality. In the end to realize a good renovation with new technics, the air tightness ofthe building is an important part. It is not just important for a successful implementation of ventilation system with heat recovery, but also for the hot air losses through the walls and other parts of the building. Techniques for energy-efficient renovation are available and tested adequately from a technical perspective. From the structural point of view, there are a lot a components to improve which can bring the house owners economic efficiency in energy issues.


Thermal insulation is a very important energy-saving measure for buildings, because well insulated buildings envelopes cut down the energy losses and that will help to reduce the energy consumption.

For an average house the heat losses can be reduced by reduced at least half. The problems that arise by installing adequate amounts of insulation in existing buildings vary enormously. The question is no longer whether to insulate, but costumers simply need to find the most efficient way of insulating each part of the home to the highest that can be afforded. The purpose of this part in the project is to give the necessary background to approach this task with confidence.

There are many positive benefits, which can be reached from insulated buildings, as well as a few pitfalls to watch out for. Besides the environmental benefit of reduced carbon dioxide emissions, there will be increased comfort, and a more even temperature around the house. Also, the heating system can be scaled down and radiators can be more freely placed anywhere in the room and, in some cases, dispensed with altogether.

The main pitfalls by adding insulation is that of creating cold bridges, where the original construction remains uninsulated and cold whereas the newly insulated surroundings are now warm. This can sometimes result in condensation, however there are solutions for most of the problems. There are very few principles to understand with insulation, and there is one concept that is worth bearing in mind:Pilar

All that insulation does is to slow down the rate of heat loss, so that less heat is required to maintain the same internal temperature. When we insulate our houses to a high standard, we not only conserve the heat from our heating appliances but also all the other sources of heat, such as from cooking and lighting, play a more important role.


This occurs when warm air meets a cold surface: the moisture in the air cools and condenses on the surface in tiny droplets of water. Most commonly, condensation occurs on the inside of single glazed windows, but it can also occur on walls and within the fabric of buildings.

Condensation is a problem that has a number of causes:

  • It can be an indication of the internal temperature being too low for the internal humidity level. This can happen in an unheated room that is not being used. The insulation of the whole building helps to solve this problem by evening out the temperatures internally, making it easier to keep the extremities of the house warm.
  • It can also be an indication that humidity levels are too high and that water vapor produced elsewhere in the home is not being vented. The simplest way of avoiding this problem is to use mechanical extract fans connected to a humidistat, in both the bathroom and the kitchen. The humidistat will switch on when humidity levels exceed a predetermined limit. It is also a good idea to keep closed the door of a room where there is a source of water vapor, this aspects will be explained in a more extended way in the ventilation section.
  • Condensation in an insulated house can also be an indication of cold bridging: where a non-insulated part of the construction protrudes through the well-insulated part and causes a surface in the interior to be at a much lower temperature than its surroundings. If the humidity level is high enough, condensation will form on this cold surface, possibly causing problems of deterioration. Cold bridging occurs most commonly at windows and where brick partition walls meet internally insulated externals walls.

Walls insulation
Roof insulation
Floor insulation
Window insulation
Air tightness
Acoustic protection

Improve building installations

When the building cover is made of high quality after the renovation it makes sense to improve the technical equipment in a building. Now the cover of the building is good enough to reduce the energy losses and therefore also the heating system can be dimensioned in a small scale. If we are talking about small scale it is much easier to implement heating systems which are not addicted to fossil fuels, but heating system which use renewable energy sources for the energy generation. The same applies for the hot water processing, which has to be determined in the same way and adapted specially for the user’s needs. These days the lighting technology makes a big effort and therefore it is easy to implement the new technology in building in a cost efficient way. The ventilation system in a building becomes more and more important, not just because of still constant air quality, but moreover the heat recovery. Nowadays the ventilation systems are able to recover about 80% of the heat which is transported through the air by exchanging with the new cold air from outside. So the ventilation system is recovering heat, which means energy saving and increasing the air quality.

6. Sources and policies

The European Union 20-20-20 Goals

Figure 4: Illusstration of the EU goals, eTactica

In these days almost everybody is talking about climate change and global warming and also this topic is very relevant and important in the whole European Union. Therefore the EU government set a goal for stopping this change until 2020. The main idea is to reduce the greenhouse gases by 20 % in comparison with 2005[5]. The amount of renewable energy should increase by 20 % and the energy should be used in a 20 % more efficient way (figure 4).

To conclude it has to be also said that the EU has proposed in January 2014 a new framework which goal is to save 30 % of the used energy by 2017. But nowadays it has not been decided if this will be binding for all member states of the EU or if this will be an individual country basis. Instead the 20-20-20 goals are general in force for all EU member states. In the following figure 18 there can be seen the different projections and current trend of the 20-20-20 from all 27 EU members (figure 3):

Figure 3: the world green building council. Energy efficiency directive. 2012

It is very important to stand out that for the study the and analysis of the different tools and techniques and the achievement of objectives on the present project, the team decided to gather and analyze information concerning the laws and politics of belonging countries of the Union European. With this, it pretends to clarify the motivations and objectives of these countries in order to obtain information about techniques which are used to achieve thereof.

Due to the characteristics of the team, it decided to analyze the policies and goals of the countries of each member (in this case: Germany, Austria, Spain and France), making easier the collection of information as well as resolving problems because of language and/or lack of awareness about policies of other countries, which could be unknown for the students.

Besides, it is interesting to highlight the interests that these countries have in matters of energy efficiency and renovation of buildings. Considering that, this information provide us a lot of data about how these countries contribute for their respective citizens to have enough tools and advice, with which to be able to face: expenses, ignorance on the matter, steps to follow in a renovation, etc.

Local Policies





7. Why renovation?

These days almost everyone has recognized, that the climate on the earth is already changing and this change is caused by human’s behavior. Especially in the last century, when the big industrializations begun, a lot of new inventions rises which are not the environmental friendliest. In the past almost nobody recognized that fossil fuels are causing climate change and so a lot of engines and machines were working with this type of energy source. However, now the civilization has realized that our behavior has to change and we must try to use as much as possible from renewable energy sources to stop/reduce this change.

The building sector consume about 40% of the total final energy and this can be prevented. But to reduce or stop this consumption a renovation is essential. So the European Union created the 20/20/20 targets, which has to be realized by 2020.

Thus in the Nordic countries of Europe, therefore was started a big project (also called Renovation Center) which is sponsored by Interreg. The members of this big project are Finland, Sweden and Norway and this project should be realized from 01.04.2015 to 31.03.2018. The main aim of this project is focused on renovations in the building sector.

Our EPS group is involved into this big project and our task is to help the stakeholders to realize a sustainable renovation. We collected information from all Europe, especially from our own countries. We are focused on information which can be implemented in the Nordic area to improve the buildings. The specialization is set energy savings, which means to upgrade the building cover like outer walls, roof, windows etc., but we are also looking for special materials which are able to resist this hard climate conditions in the north of Europe. In the end we want to inform stakeholders the following:

  • How to renovate their buildings in a sustainable way.
  • How to save energy.
  • Which materials to use for a renovation.
  • How to prevent building damages like mold, moisture damage, etc.

During the last years the climate change is a permanent guest in the mass media all over the world. Almost everyone is discussing this topic and searching for the best solutions to stop it. The interested party is not just the average world population, but there are quite a lot interested people from the high society too and of course the specialists from the sectors science, economy, politics and culture. Nowadays, the majority of the population has recognized, that something is changing on our planet and it is not controversial anymore.

The technique to save energy is already developed and we also have the skills to implement it to our life. However, all these information are not gathered in a simple or efficient way, therefore it is necessary to encompass and share them that everyone can understand it, thus the present project was born in order to achieve this goal.

European Union with the member states agreed, to decrease all the energy waste and also to save the environment and beat the climate change. The next set objectives for all members are the 20-20-20 goals, which has to be realized until 2020. After this, the European Union already set the next goals for 2050 and to prohibit the climate change the greenhouse gas production has to be neutral in the second half of this century.

The building sector is one of the biggest energy consumer in Europe, especially the residential buildings needs more than 1/3 of the whole end energy. Therefore, it was established in this report how the different stakeholders could renovate their houses or buildings to reduce their consumption.

Besides it is important to stand out that the present project is a part of a big already ongoing project, which takes part in the Nordic countries (Finland, Sweden and Norway). The main sponsor of this project is Interreg, as well as some other companies and universities from the Nordic countries. The main task is to inform stakeholders how they could renovate their buildings in a sustainable way. The quality of the building should of course increase after the renovation, but not just in one aspect to save energy, also to improve the quality of living. The report includes the necessary information about renovation and an idea how an online sharing platform could look like.

In our research we found a lot of documents with useful information. Nowadays, on the internet is a lot of data available, for our specific topic as well. For this reason the difficulty is not to collect information but to sort and utilize the different results. In our particular case it was also necessary to cut down information to the Nordic countries.

The basement how to realize a sustainable renovation is done. The report includes information about building cover, building installation and how these new techniques affect the indoor environment quality. Apart from their effect on the living environment, also the criteria which are important to observe during a renovation are included. These collected information we would like to share with stakeholders easily and according to that we created a basis how a webpage should look like. It does not matter what the interested person is looking for, in the end the webpage structure should lead to the end product which the person was searching.

We also have to say, that the technique and the knowledge to reduce the energy demand is available in the European countries. However, now the population must be convinced to start to reduce their own energy demand and this is only possible if the technical equipment and the operation costs are affordable. Therefore, in our opinion the government has the big tasks to support their citizens in a financial way and to lead them to an energy saving behavior.

One of our first tasks in the project was to inform ourselves, what is going on in our home countries, the different roadmaps to reduce the energy consumption. In addition we have to say that in each country there are plans to stop the wastage but every roadmap is quite different. However, in every case it is not easy to follow those maps.

In the and we have to say that not just the average population in their detached houses or apartments have to change their behavior and improve their building to more energy savings but especially the big players like the Industry must contribute and prohibit the climate change.

8. Case conclusions

In general, the most of analyzed cases try to reduce energy consumption in buildings, which were usually built in the 70s or earlier with poor quality materials and without any consideration for energy saving. In addition to pretending to obtain a significant reduction in consumption also it tries to increase the quality of life of tenants, providing greater comfort at home, either by improving air quality, reducing noise or making life easier the tenants.

The observed renovation techniques are very varied from one company to another one, but there are a series of basic principles which are carried out in each described example, as well as in analyzed ones along the project. I could be said that the renovation of a building with the intention of being energetically efficient follows a series of guidelines and steps in order to obtain the desired reduction in consumption while improving the comfort.

According to the analyzed studies of energy consumption, the most of the energy consumption of a building focuses on air-conditioning and hot water production. Therefore, the renovations almost focus on these systems totally.

  1. An efficient way to reduce the heating consumption is to prevent heat losses between inside and outside of the building as these cause that he heating system have to work longer and with more power in order to reach the desired temperature. These heat losses usually proceed from thermal bridges, poor airtightness in the rooms, etc.
  • Thus as it can be seen in all the refurbishments practically, it is usual to work with the thermal insulation. Many of these buildings do not even have insulations on their walls, especially in buildings which are situated in warm climates such as Southern Europe while in cold climates it is usual to find insulations but these ones are usually insufficient or with poor quality. In all cases which have been analyzed it has observed that insulations play a very important role in the renovations. The ideal is that the original insulations should be changed for new ones with better properties (such as thermal conductivity) on walls, floors and ceilings.
  • Another important point is the facade due to it plays a key role in the process as it is the outermost part of the building envelope. The usual practice in these cases is to demolish the outer layer of the old facade and place new prefabricated elements, which are easy to install and inexpensive to produce, providing a low thermal conductivity between inside and outside of the building. In the 4 discussed examples the new facades are usually wooden prefabricated elements which have already an included insulation; also it is possible to see that its installation is very simple. Finally it is covered with tiles in order to get a new and flashy esthetic.
  • The inclusion of triple-glazed windows or windows for passive houses, which have fantastic properties to prevent heat transfers, reduces significantly energy losses. As shown in the cases, the renovation of windows is an important factor in order to achieve the objectives of the renovation due to they are sources of appearance of thermal bridges. In its installation it does a special emphasis on their frames and connection with insulations of the walls. It is often the use of plastic covers in order to avoid problems with cold climates.
  • As for the airtightness it is important to comment that when a low value of itself is achieved after the renovation. It is advisable to install a mechanical ventilation system which renews the air, avoiding that it spoils. This could cause a sense of discomfort in the tenants.
  1. Another way would be to change the air conditioning system for another one which is more modern and based on energy efficiency. Currently, on the market there are a large number of brands which provide these types of systems with high quality and high capacity to save energy.
  • Right now it is normal to install a heat exchanger, so that this can leverage the own energy of tenants, as well as the provided energy by the heating system before. So the system would not need the same energy to heat the air which enter from outside because it has already been warmed up previously.
  • The upgrading of radiators is also an element to keep in mind because its technology has increased enormously in the last years. If it adds to this the renovation of heating ducts (hot water too) for other ones with insulation and better materials, the reduction of energy consumption is notable.

Other two important points, which have to be commented, are the cost and working period of the renovation. Along the study, it has been possible to observe that the budget for the different refurbishment varies hugely from a country to another one, for example it is difficult to compare budget between cases in Finland with cases in Bulgaria or Rumania, where the labor is pretty cheaper than in Finland or Sweden. Anyway, the cost goes intrinsically bound with the fixed objectives. Regarding to the work period, the cases vary between them. The experience is an important factor in this case, because experienced workers will finish the work before than a worker with little experience in this kind of techniques. Also there are differences between the cases because some of them work in a building too big or with several buildings on the same project

Company: Swedish Environmental Research Insitute Ltd
Author: Jenny Gode
Company: Die klimaaktiv Datenbank
GreenHouse Studentenwohnheim D5.B-4, 1220 Wien
BeBo, 2012. Brogården
Miljonhusen blir passive
SINTEF, 2013
Company: Residential Renovation towards nearly zero
SINTEF, 2013. Presentasjon av casestudier i REBO