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