Estonia has a long-term renovation strategy target of 14,000 renovated apartment building in 2020-2050. The KredEx renovation grant system has brought on significant results in deep renovation. Since the first scheme of the grant system, there are improvements in ventilation requirements.

Estonia has achieved great results in deep renovation, thanks to the KredEx renovation grant system. Backed by the EU since its 2010 kick-off, KredEX features strict technical requirements, focusing on high-level energy efficiency and indoor climate conditions.

Large-scale renovation has generated positive effects on the macroeconomic level, quantified in terms of job creation and tax return. All in all, 17 jobs per 1 million euros of investment in renovation have been created directly and indirectly per year in Estonia. Tax revenue from renovation construction projects has been quantified to be 32–33 % of the total renovation project costs. Therefore, evidence from Estonia shows that a state subsidised renovation has been, in practical terms, budget neutral with direct financial support of 25–40 % used in last 10 years.

During this decade, around 1,100 apartment buildings have been renovated. Energy efficiency and indoor climate conditions comparable to modern apartment buildings have been achieved with deep integrated renovation. At the same time, it’s worth taking note that the cost of deep renovation is approximately 3–4 times lower than building a new apartment building. This is a good start, but the volume needs to be increased to catch the long-term renovation strategy target of 14,000 renovated apartment building in 2020-2050.

Challenges in indoor climate quality during the first scheme

Support from the EU first materialised in 2010-2014, as a total of 663 apartment buildings underwent renovation in Estonia. This first period showed what can go wrong and what needs to be improved in renovation. Typical to any new scheme, KredEx started with well-defined energy saving targets, but technical requirements for ventilation were not specified. It was just stated that indoor climate quality should follow Category II indoor climate target values typically used in new buildings according to European standard. In reality, such general requirement was not followed and many ventilation solutions failed. That especially applied for single room ventilation units with heat recovery which were noisy, had frost problems and were overrun by stack effect in high-rise buildings.

Developed scheme with new ventilation requirements

Crucial development was made in the new grant scheme, KredEX II, emerged for 2015-2017, with a total of 102 million euros in EU Structural Funds used. Under this new scheme, technical requirements and the application process were further developed and more detailed. Now the starting point was that heat recovery ventilation systems are to be installed in order to achieve substantial energy savings (about 70% in heating) and indoor climate improvements at the same time. For that purpose, two technical ventilation solutions were specified for a common large renovation grant (35% support at that time). These solutions were mechanical supply and exhaust ventilation with heat recovery or ventilation radiators with exhaust air heat pump. Both systems have been widely used. There was a significant innovation to install ventilation ductwork to façade into new additional insulation layer that made centralized heat recovery ventilation feasible. Exhaust air heat pump with ventilation radiators has been popular in higher buildings where main ducts become bigger and are more challenging to install to façade. Together with ventilation system specification, ventilation airflow requirements were set on room level, telling how much supply air is needed in bedrooms and living rooms and how much extract from toilets, bathrooms and kitchens. These new requirements made design transparent, KredEx also started to evaluate the compliance of design documentation by external consultants. Finally, the airflow measurement protocol requirement after installation ensured that ventilation was well done in all projects.

The same technical requirements have been used during last years, but now the scheme has developed with regional development considerations. While a large grant in Tallinn and Tartu was limited to 30% support, projects in smaller cities received 40% and in Ida Virumaa even 50%.


Jarek Kurnitski, professor at the Tallinn University of Technology, is a distinguished researcher in the field of energy performance and indoor climate of buildings.

Apartment buildings from the 1960s and 1970s in Finland are usually given an energy efficiency rating between D and F. Renovations have the potential to improve energy efficiency and lower the climate impact of housing.

Over a third of apartment buildings in Finland were built in the 1960s and 1970s. The repair debt of this housing stock is a challenge – these apartments are typically in need of an extensive renovation.

Energy efficiency improvements and updating of the heating systems are typically carried out in pursuance of rehabilitation. The rehabilitation projects provide an opportunity to lower greenhouse gas emissions. In addition, the energy subsidy granted by The Housing Finance and Development Centre of Finland (ARA) since 2020 is accelerating renovations in Finland.  

Suburbs in Helsinki, Joensuu, Turku and Vantaa  

In this blog post we examine the characteristics and present state of building stock in Helsinki, Joensuu, Turku and Vantaa, in particular the suburbs. These cities are involved in the newly launched Decarbon-Home research project, which studies, among other things, the energy efficiency of suburbs, energy renovations and socio-economic factors, segregation and residents’ views on housing and energy solutions.  

The age of the urban building stock varies from region to region according to the stage when the population has grown. For example, in Helsinki the share of the old apartment houses is significantly higher than in other cities. On the other hand, the population of Joensuu and Vantaa has grown rapidly since the 1960s, which is reflected in a large part of the newer building stock. In Turku, almost half of the apartment buildings were built in the 1960s and 1970s. 

Modest level of energy efficiency 

The majority of apartment buildings built in the 1960s and 1970s are quite modest in terms of energy efficiency as the energy efficiency class varies between D and F. In Helsinki and Turku, some apartment buildings reach the classes B and C, while in Joensuu the best are rated D. In Vantaa, even 62 % of the apartment buildings from the 60s and 70s in the energy certificate register belong to category F. Helsinki and Turku, the building stock of the 60s and 70s has slightly higher ratings compared to the whole country. 

Based on the building and dwelling register, district heating (89%) and oil heating (9%) are the most common forms of heating of apartment houses. Almost all apartment buildings built after 1980 are connected to the district heating network. Among the four cities under examination, Turku and Joensuu have most oil-heated properties. On the other hand, in recent years, some residential apartment buildings have disconnected from the district heating network and switched to geothermal heating, for example. 

Increased segregation 

Although the segregation of residential areas is a topical issue in Finland, and this debate often focuses on suburban areas, the socio-economic development of suburbs has been studied relatively little since the 1990s. The reference we use in this blog post is Stjernberg’s analysis of the socio-economic status and development of the Helsinki region’s suburbs built in the 1960s and 1970s, published in 2017. The data  ends in the year 2014. 

Helsinki was one of the least segregated capitals in Europe in the 1990s, but since the 1990s, socio-economic disparities have increased both in Helsinki and elsewhere in the Helsinki Metropolitan Area. This is particularly pronounced in certain suburbs that have lagged behind other areas. Certain socio-economic differences are emphasized in the suburbs built in the 1960s and 1970s in the Helsinki region compared to the average figures in the Helsinki region. For example, there are more unemployed, foreigners, aged (over 65) and people with low income and low education than in average. The share of rented apartments varies significantly between different suburban areas although according to general conception, suburbs are dominated by rental housing. In some of the suburbs of the Helsinki region built in the 1960s and 1970s, more than 80 per cent of the housing stock consists of owned apartments, but in others the share is less than 20 per cent.

In the Decarbon-Home project, we study the residents’ characteristics described above also in other suburban areas in Finland. We will explore, for example, how unemployment, low income or the high age of residents affect the possibilities for improving energy efficiency. 


Hanna-Liisa Kangas works as a senior research scientist in climate and energy policy at the Finnish Environment Institute. Research and promoting climate-wise construction is a matter of heart for Hanna-Liisa, because something must be left of this planet for future generations.

Santtu Karhinen works as a researcher in energy economics at the Finnish Environment Institute. Santtu is particularly interested in energy efficiency issues of buildings and will soon be able to use this knowledge for his own building project.