Building the future: The Tammela phenomenon – successful renovation of apartment buildings

VTT joined forces with the City of Tampere and local limited liability housing companies and began renovating some apartment buildings built in the 1970s and 1980s to improve their energy efficiency. The customised solutions and final outcomes far exceeded everyone’s expectations.

Four years ago, I walked with a colleague of mine in the area around Tammelantori square, getting acquainted with the blocks of flats there. The City of Tampere, in collaboration with VTT, had organised an open application process to identify local limited liability housing companies that were willing to become demonstration projects for improved energy efficiency. We felt that we were beginning the process much too late. The windows in the buildings from the 1970s had been replaced, and many of the houses had received new façades. The city, however, wanted to focus on the district of Tammela.

Energy efficiency improvement via a staged approach

From among the applicants, we were able to select eight limited liability housing companies to which we applied the principle of a ‘staged’ deep renovation of building stock included in the Energy efficiency directive. According to this principle, the energy efficiency of buildings can be improved by means of a staged renovation. Only two of the eight housing companies selected for the demonstration implemented the renovations of both façades and technical systems at the same time. Two other companies had already done some improvement measures.

On these four demonstration sites, improvements in energy efficiency were achieved by replacing the windows, installing additional insulation on the façades, renewing the lighting in the common facilities and installing a heat recovery and exhaust air heat pump. Furthermore, adjustments were made in the building’s technical systems, which included reducing the supply pressure of domestic water. The same measures, with the exception of additional insulation, were implemented in three other sites. One of the sites only invested in different types of heat pumps. In addition, all the sites implemented some other minor refurbishment measures.

Concrete turned into a real gem

Every housing company needed an active moving spirit for the project, either a chair of the housing company board or a house manager. One of these persons also happened to be an enthusiastic housing investor, who understood the financial incentive associated with the pilot. In some of the companies, choosing to join the pilot took no more than a single housing company meeting, whereas others needed several sessions before reaching a decision.

Now, subsequently, more than 90% of the housing company share owners have been satisfied with their decision to become one of the pilot sites in the EU GUGLE project. The residents of the demonstration that was the last to be completed are particularly proud of the results: they present their house as a gem among the contemporary housing stock of basic concrete buildings around it (photo).


Energy savings amounting to a significant 40%

The impact of the EU GUGLE project is not limited to the pilot projects. When we were looking for pilot projects four years ago, hardly anyone was familiar with heat recovery and exhaust air heat pump technology. The technology has made its breakthrough in the market over the last four years. The monitoring of the EU GUGLE projects and open communications about them have played a key role in this.

Cooperation with the housing companies has raised many questions about general claims. In the EU GUGLE pilots, the decisions were eventually quite easy to make. One housing investor promoted the renovations in his housing company, the senior residents in the housing companies involved were enthusiastic about the matter, and, on top of everything else, energy savings were achieved. To date, the combined energy savings calculated from the pilot projects have amounted to 40%. The monitoring of the pilots will continue for a further two years.

Further information on the pilot projects:

Terttu Vainio VTT

Terttu Vainio, Senior Scientist
terttu.vainio (a), +358 40 508 0983

Building the future: Renovate properly – a new guide to renovation

When well-executed, renovation brings a number of benefits to the users and owners of buildings. A published guide presents the latest information for those intending to perform renovations and outlines the benefits – such as comfort, long-term energy savings and retention of a property’s value – of highly improved thermal insulation levels.

‘If it ain’t broke, don’t fix it’, but when renovation is needed, it is worth doing it properly. Renovations present an opportunity to markedly improve a range of factors affecting how well a building functions. For example, in many cases thermal insulation can be improved well beyond what the regulations stipulate. A successful renovation requires that the building is seen as a whole and the interactions between different systems are known and taken into account.

The guide presents issues that must be taken into account in renovations, such as sufficient planning time, the necessary background information, official regulations, the commissioning of further surveys and engaging a supervisor for the project. These issues are described from the perspective of a typical apartment complex, for which external expert assistance is particularly needed. The objective of the renovation, from the beginning of the planning, should be good indoor environment and high energy efficiency.

Signe Brander, Helsingin kaupunginmuseo

Picture: Signe Brander, Helsinki City Museum

When renovating, renovate properly

When a renovation project is well planned, executed and supervised and the thermal insulation level is markedly improved, several features of the building can be enhanced:

  • The property’s value
  • Thermal comfort
  • Reduced need for heating
  • Maintenance need
  • Stability of the internal temperature
  • Sound insulation

Renovations should not impair other functions of the building, and they should also assist in the implementation of forthcoming renovations. In particular, proper ventilation of the premises should be ensured at various stages of renovation. Maintenance and repairs are a continuous feature of good property maintenance.

The guide also includes a number of examples of renovations, but these cannot be considered as universally applicable solutions. When renovating building structures, the starting point is the condition of existing structures, i.e., suitable renovation methods must be evaluated on a case-by-case basis. First priority is to ensure the elimination of the causes of previous damage and then include other improvements for the building envelope.

Published in May 2017, the guide Rakenteellinen energiatehokkuus korjausrakentamisessa (Structural energy efficiency during renovations) was drawn up in a project funded by the Ministry of the Environment, the Confederation of Finnish Construction Industries RT and the Federation of Finnish Woodworking Industries. The project was completed by VTT.

Korjauksen toteutuksen ja kustannusten hallinta

Sufficient investment (labour, time), at an early stage, in analysing the state of the building, renovation needs and project planning enables the appropriate setting of objectives, as well as the implementation of repairs and the related cost control.

Rakenteellinen energiatehokkuus korjausrakentamisessa -opas

The guide has been published in printed form and is available as an e-book and in PDF format from the following websites:

Tuomo Ojanen VTT

Tuomo Ojanen
Senior Scientist

Building the future: Bold implementation generates infra and construction sector innovations

Much is being written, in various contexts, about the experimental culture. This is a favorite term used by the current government. The idea is to achieve rapid growth, innovative solutions and improved services, while promoting self-reliance and entrepreneurship, and strengthening regional and local decision-making and cooperation based on practices developed at grass-roots level.

In the development of the construction sector, design and building and traffic infrastructure development, piloting has become a common term when innovating in project activities. New technologies should be tested in genuine project environments, so that their potential and true benefits can be revealed in a joint construction project between several organisations. An extensive piloting project can include several trials and even experiments of alternative ideas, in which the aim is to develop a good and adaptable operational plan for the project. A topical theme in piloting is the use of information management and inframodels in infrastructure construction.

Information is part of the final result

A project based on building information model involves the same actors as in other construction projects. Service contractors (designers, consultants, contractors, fitters) perform project tasks and generate, share and release the related information for each other, project managers and the client – structured as agreed. The client is provided with an actual building or route and the information required for its maintenance and use across its lifecycle.

Building information technology is applied as part of process renewal during a project. This enables the testing of interoperability between tools, in terms of communicating information, as well as process integration and collaboration between actors. Each actor’s mindset is oriented towards generating efficiency and information for project decision-makers and other parties. Such information should be defined, suitably precise and localised for the geometrical plan (building information model). It should also be provided at the right time and in a format compatible with the tools of the various actors within the collaborative process.

Pilot projects involve the development of information modelling requirements, in which tried and tested practices are defined as minimum requirements and instructions. Developmental implementation is an efficient way of operating. In pilot projects, the socio-technological change can be realised in a way that it strengthens and modernizes the sector and service providers’ business operations. The built environment, and its service-capabilities, are experienced positively by end-users.

The client is the key player in projects using building information models

The client acquires the overall assignment and key experts, and defines the technology to be used. In this regard, the client is the key actor in projects using infraBIM models. The general infraBIM model requirements, YIV2015, define the relationship between the client and the service contractor within a set of instructions: A building information modelling (BIM) project works as follows: “The client must be able to assess how BIM can generate the greatest possible added value for the project and how modelling will promote the achievement of the project’s overall objectives. On the other hand, the project’s service contractors must be able to adapt their business processes to the client’s objectives”

Example: BIM for the City Rail Loop project

Collaboration between the client and service contractor is particularly important in pilot projects, where the goal is to develop the best operating models for the use of technology. The design of a railway line and buildings for the City Rail Loop project is a recent example of an extensive pilot environment for BIM development.

The clients in the City Rail Loop project – the Finnish Transport Agency and the City of Helsinki – did not lack the courage needed to require that all planners and designers involved must engage in BIM from the very beginning. The clients had to enable a smooth collaboration process between several dozen representatives of the design sector. Even defining the correct initial data was acknowledged as challenging, as was the information management required to present an overall picture of progress with the project; this was because two sectors, using different types of BIM software, were working on the same project. This succeeded via an innovation process, which received sufficient support through means such as a BIM management group able to decide quickly on integration challenges as they emerged. Interoperability, enabling information exchange, was achieved through definitions created by a BIM coordinator development group – the scope and usefulness of modelling turned out to be better than anyone had originally dared hope.

The final result was the first international project in which representatives of the infra and construction sectors engaged in modelling using their own planning tools, but using information exchange standards and mutually agreed guidelines. VTT has had a report drawn up on the BIM guidelines issued by the client for the City Rail Loop project, which explains the practices developed and the lessons learned.

Open-minded and bold people able and willing to engage in development are needed in research, development and implementation. The ability of clients and their representatives (design leadership and project managers) to adopt new know-how has a direct bearing on how well extensive infra-modelling based on a PRE-research programme ultimately succeeds.

The BIM development pilot for the City Rail Loop project shows that innovation occurs at project level if enthusiasts for new technology are given the space to develop effective practices. To create value, the technology must be adapted to the processes in question and generate practical methods.

Every major construction and infrastructure development project is a possible platform for a pilot. Collaborative process models can be changed in large-scale projects, if innovations form part of the project goals. Piloting is monitored and used to evaluate the stage of development of new practices. A good pilot project aims to achieve longer-term goals than a single experiment: at best, it forms part of a sector’s development roadmap.

Tarja Mäkeläinen VTT

Tarja Mäkeläinen
Senior Scientist

Building the future: Toolkit for sustainable urban planning

City planning sets the long-term framework and goals for the development of the built environment for the coming decades. The urban planners’ work is challenging, as they should be able to assess now how to build our future living environment and what it will be like. VTT has developed several supporting urban planning tools, which enable showing of the impacts of planning choices for decision-makers, residents and other stakeholders.

The purpose of city planning is to set the general guidelines for construction and urban area development. They enable the development of a comfortable, efficient and environmentally friendly living environment. There are several stakeholder groups involved in urban planning, each with its own interests, opinions and perspectives. The urban planners’ role in the process is challenging, as they have to find compromises that will take account of the area’s special features and support ideal development of each area in an individual way. They should be able to estimate how the planning choices affect the area and what kind of consequences they will have on the area’s sustainable development throughout the whole life cycle. Several studies have concluded that the reductions in greenhouse gas emissions required for mitigating climate change are finally made at a local level. City planning is one of the most important practical tools cities have for putting sustainable development goals into practice.

The choices made in the course of the city planning process affect, for example, buildings, housing and services, traffic, the choice of potential energy sources, and the general functionality and attractiveness of the living environment. Decisions need to be made regarding the placing of housing, services and workplaces, recreational areas, and promotion and provision of support for various modes of transport. Sufficiently dense urban structure enables a profitable public transport infrastructure, provision of neighbourhood services, and city’s energy system (e.g. district heating). The local city plan and its terms and conditions applied to plot transfer can include recommendations and offer incentives for planning and selecting eco-efficient solutions.

The energy efficiency requirements for buildings are becoming stricter, and by 2020, all new buildings must be nearly zero energy buildings in Finland. Successful city planning provides the best possible starting point for designing of nearly zero energy buildings. For example, aligning buildings southward facilitates efficient utilisation of solar panels and solar thermal collectors. Local traffic planning, on the other hand, takes a stand on which modes of transport the residents, workers and other local transport users choose in their everyday lives.

It is important that the choices made during the urban planning process are assessed and evaluated in the long term. Most often, the impacts of sustainable development are divided into environmental impacts, economic and social impacts. To support urban planning, VTT has developed the CityTuneTM toolkit (see the figure below), which can be customised to meet the needs of each specific customer and city. CityTuneTM consists of a large selection of assessment methods and tools, including: the Smart City Index suited for the assessment and benchmarking (The main results of the CityKEYS project), urban planning tools (Eco-calculator for city planning, KEKO), forecasting tool for the energy demand of built environment (Method for assessing energy efficiency potential and emission impacts in the building stock, REMA), energy planning and optimization tool (Results of the CITYOPT project), and APROS software for precise simulation of energy systems. This toolkit enables to assess the choices made in urban planning as accurately as needed. The results obtained make it easier for the city planners to explain the choices made and show their impacts to the decision-makers and the residents. In addition to the developed technical solutions and methods for assessing the environmental and economic impacts, VTT has also developed solutions for Living Labs supporting two-way communication between urban planners, decision-makers, residents and other users of an area. It seems that communication facilitates and accelerates the implementation of the urban planning process, which may be very time- and resource-consuming with several commenting rounds.


Indicator model for the assessment of smart cities and the related CITYTuneTM toolkit, which helps to optimize choices made in urban planning
from the very early stages of planning.

Mari Hukkalainen VTT

Mari Hukkalainen
Senior Specialist

Building the future: VTT’s research into the built environment generates innovations for a low-emission society

Thank you for joining the readership of our “Building the future” blog series. This series presents visions by our specialists of future building concepts based on robust research data.

In buildings 40% of all energy is consumed and they account for 30% of all emissions. The objective of VTT’s research into the built environment is to envision a low-emission society with spaces and buildings that provide comfortable and healthy environments for living and working.

VTT’s multidisciplinary research into the built environment is renowned in Finland and internationally. Innovations developed jointly in international research projects are adapted for efficient utilisation in Finnish conditions, with the results benefiting both Finnish society and the Finnish business sector.

This blog series contributes to bringing the results of research into the built environment to the attention of the general public. Blog posts are written by research scientists, and provide readers access to the latest research results.

You find all the blog posts here.

Riikka Holopainen VTT

Riikka Holopainen
Research Team Leader

Major changes ahead for district heating

Many of us live in apartments that are warmed by district heating. In our daily lives, it doesn’t necessarily occur to us how effortlessly our apartments are warmed and that breaks in heating are rare, brief and barely affect our comfort. Radiators and thermostatic radiator valves, which we don’t even need to touch to maintain a pleasant indoor temperature, are all that remind us of heating. However, district heating will most likely undergo major changes over the next decade.


District heating has a long history. The world’s first systems were implemented at the end of the 1800s. In Finland, the distribution of district heating began in places such as Helsinki and Espoo in the 1950s. Most district heating is still produced by either combined heat and power plants, or separate heating plants. However, the trend is shifting from the current third-generation district heating towards fourth-generation district heating systems. The long-term trend has seen improvements in the energy efficiency of district heating and a fall in water temperature levels during the transition to the next generation.

District heating is more and more often being produced from renewable energy sources and various types of waste heat, which would otherwise remain unused. For example, several data centres have recently been built whose facilities generate a great deal of heat. Waste heat of this kind is already being used as a source of district heating. In the sample calculations for the EFEU research project, carbon dioxide emissions were reduced by half, while a fifth of the district heating produced for the studied area comprised waste heat from the data centre.

Towards changing markets

The district heating markets are also changing. An open, two-way district heating network means one that both distributes district heating to consumers and enables customers or individual heat producers to sell their surplus or other generated heat to the network. This could mean a major increase in the share of, say, solar power or large thermal heat pumps in district heat production. In the EFEU project, it was observed that, since solar and geothermal heat saw the biggest increase during the twenty-year study period, the need for centrally produced heat fell by 34%.

In an open district heating production structure, the operators will also change. Someone must take responsibility for the trade in heat and the related production and demand management. It must be decided under what terms and with what technical solutions trade can be made possible, how demand during peak consumption can be met in all circumstances and how investments will be made.

As the temperature levels of district heating water fall, household heating systems will have to be upgraded. The latest systems are so-called low-temperature systems, whose radiators – for example – are bigger than the current ones. Changes can be implemented during other renovations, which makes them cheaper than when done separately. A building’s heating distribution system would then be ready for either the person’s own renewable energy system, or for the new network – freedom to choose is a blessing.

In the future, network operators may also encourage customers (by using tariffs, for example) to prepare for connection to a low-temperature network. For network operators, lowering the network temperature will open up new markets, such as the possibility to buy and utilise cheap waste heat. In addition, energy-renovated buildings previously disconnected from the network in an ‘old district heating network’ area could reconnect, or new buildings with their own heat production could be connected for the first time. In practice, however, changes in buildings’ systems will occur in stages and only in new district heating areas to begin with.

EFEU research project

Energy system scenarios were created via the Efficient Energy Use (EFEU) programme coordinated by CLIC Innovation Ltd. The scenarios involved research on increasing the use of solar heat and geothermal heat pumps, industrial waste heat recovery, and the impact on energy and emissions of small-scale producers selling heat to consumers. These options were explored in a case study of the Central Uusimaa district heating network.

The publication, ”Visions for future energy efficient district energy systems”, is available online at:

The report sets out visions of the energy systems of the future and the current status of systems connectible to district heating in Finland. The publication describes the challenges, needs and scenarios related to future business activities and services.

Satu Paiho, Senior Scientist

Rinat Abdurafikov, Research Scientist

Energy efficiency is the key component of sustainable development in cities


The UN Habitat New Urban Agenda was released a few weeks in Quito, Equador. The task to write a new urban agenda has not been easy, given that pre-conditions and interests are different in different UN countries. At the same time, there is an urgent need to act in favour of sustainable development in cities.

The striking fact is that urban settlements covers roughly 2.7% of the surface area of the globe, but consume 70% of resources and hence produces 75% of CO2 emissions. Moreover, we face many challenges if we are to transform our cities into healthy, safe and comfortable living and working areas.

Starting from these pre-conditions, the New Urban Agenda for the first time highlights the importance of energy. As is well-known, energy production is the main source of CO2 emissions and air quality problems in cities. Energy is needed in cities for transport, heating, cooling, lighting as well as for water and sanitary systems. We also need energy to run equipment and appliances. To transform ourselves into low carbon society, we need to de-carbonise our energy production, but also, very importantly, we need to use energy more efficiently. Energy that does not need to be produced is the most environmental friendly. Energy efficiency is not only beneficial in preventing pollution but is also a key component for resilient cities. Energy efficiency entails reducing overall demand and more importantly reducing peak demand. In combination with smart technologies, demand can be controlled based on self-learning and adaptive algorithms to reduce and shift the demand even more efficiently without compromising users’ well-being, but rather in ways that can also further enhance well-being.

Smart cities and efficient resources

In addition to energy, the concept of smart cities was for the first time raised onto the agenda. The concept of smart cities is quite unique, since it is applicable both to industrialised cities/districts and to developing economies. The benefit of smart cities is that by using easy-to-install and adaptable sensors and self-learning control algorithms, existing infrastructure can be made more efficient. Moreover, new methods allow for generating urban services more efficiently in developing countries, without heavy and costly infrastructure requirements. Good examples for this are the implementation of renewable energy sources for cities and communities. In addition, smart communications enable citizen engagement and ownership within their own living areas, which evidently improves the perceived living quality and attractiveness of the area.

Smart systems enable us to use our resources more efficiently. This can be done by using and combining data from different sources. Currently, in modern buildings, there are typically over 20 000 data points, and hence in cities there exists an unimaginable amount of data; it is evident that no-one has the capacity to process all the data. We need, therefore, smart self-learning and predictive systems to make the most of the data available. One of the leading principles in smart cities is to enrich data to create meaningful information that supports our decision-making and helps in making our everyday lives run smoothly and that helps us to achieve environmental sustainability. More importantly, this saves time for the most important things in our lives.

Miimu Airaksinen
Research Professor
UN Habitat Policy Unit 9

Miimu Airaksinen was nominated in 2015 as an expert for the United Nations Policy Unit 9 on Urban Services and Technology to prepare the UN urbanization strategy.

Twitter: @MiimuAiraksinen