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How can we implement a seamless Renovation Wave in Estonia?

Einari Kisel, Targo Kalamees, Ergo Pikas, Innar Liiv, Endrik Arumägi

The biggest challenge of the European Union's Green Deal, which is largely not yet even discussed, is to renovate all the buildings that are still standing by 2050. A few years ago, a study by the TalTech Department of Civil Engineering and Architecture pointed out that, in Estonia, this would mean renovating nearly 60% of today's buildings (the rest are either at a good level of energy efficiency or will be demolished by 2050) and it would cost nearly 25 billion euros. While currently nearly 1% of buildings are renovated annually in Estonia, the volume of renovation should be at least fivefold in the peak year to achieve this goal.

Today, the responsibility for renovating buildings primarily rests on the building owners. At the same time, the vast majority of them lack financial resources, knowledge, and the will to undertake renovations, although the return on such investments at current energy prices can be 3–5 years, not to mention the increase in real estate value. Although the state has been supporting the renovation of apartment buildings and detached houses for many years through Kredex, the majority of buildings (especially in rural areas and shrinking cities) are still not renovated. In most cases, emergency repairs are done, but only a few dare to renovate the building completely. In many cases, the owners of the buildings do not provide the local government with information about the construction and repair works that are being carried out.

The ‘Renovation Wave’ strategy of the European Union envisions that, in these situations, local governments should become the leaders of the entire renovation process. Currently, local governments only have the approving role, giving approval to building and use permits. However, if local governments develop an understanding of how to comprehensively and rationally renovate buildings and even city districts to be energy-efficient and climate-neutral, they would also be able to offer support to building owners in making decisions and arranging financing.

However, in order for local governments to be able to provide such a service, they must have a clear overview of the most expedient way to renovate specific buildings and city blocks. When moving towards climate neutrality, the potential of different buildings in contributing to it should be analysed. There are situations where  it is not possible to achieve an energy efficiency class of A or B, for example due to heritage conservation restrictions. However, if a building next to it or in the same area is renovated into an energy-plus building, ie where more energy is produced with solar panels, for example, than is consumed, it is possible to achieve climate neutrality objectives by district.

In order for local governments to be able to share such information with building owners, comprehensive renovation strategies for city districts should be drawn up. Such a strategy would provide information on the energy efficiency and climate neutrality potential of a given area, the size of investments needed for each building, and what renovation measures should be used.

Renovation strategy tool RESTO

RESTO pilootala.jpg

At the beginning of 2022, a pilot project was launched in cooperation with the city of Võru, the FinEst Centre for Smart Cities, the TalTech Department of Civil Engineering and Architecture, and the Department of Software Science to create a digital tool that local governments can use to prepare regional building renovation strategies. In the future, this tool must help local governments to support building owners in the preparation and implementation of comprehensive renovation projects, to assess the volume and effects of investments in the joint renovation of buildings, and to find the best technical solutions based on the characteristics of specific buildings. The pilot project is called RESTO, which is based on the words REnovation STrategy TOol, and it is financed by the Ministry of Education and Research and the European Regional Development Fund.

The purpose of the RESTO tool is to collect data from various databases (the building registry, the Estonian digital twin created by the Land Board, registers related to heritage conservation restrictions, etc) about the buildings in the observed area and compare their energy efficiency with the best renovated buildings. Based on nearly 500 parameters, the model analyses around 6,000 renovation possibilities for each building and suggests how the buildings in the given area should be renovated in such a way that it is possible to ensure the objectives of energy savings and emission reduction and optimal costs for the building owners, while not contradicting various building restrictions. RESTO also reduces the workload of planners and designers, renovating buildings together makes this activity more attractive for construction companies as well, and overall costs and bureaucracy related to building renovation are reduced.

In the city of Võru, the aim is to test the functionality of the created tool on the buildings of the residential quarter bordering Kreutzwaldi, Tartu, Vee, and Vabaduse streets in the city centre and prepare a sample renovation project for one apartment building in the heritage conservation area.

Plenty of challenges

The first year of the pilot project was spent checking the availability and quality of building data from various databases, developing calculation methodologies, and negotiating building restrictions. As one might expect, the building registry data on buildings, for example, are mostly quite inaccurate and do not reflect the actual situation. To solve the problem, TalTech researchers together with Kredex have analysed the technical indicators of more than 400 buildings and developed a database of so-called reference buildings, which can be used to evaluate the energy efficiency of similar buildings. Programming and additional analysis of computational methodologies are currently being carried out at TalTech. In cooperation with ministries and other state institutions, solutions are also being sought to enable the model to be used as widely as possible in Estonia and other countries in the future.


In parallel with the development of the model, the Võru city government, through a public tender, selected one pilot building located in a milieu valuable area (at Kreutzwaldi 2), for which a model project of a complete renovation will be prepared in order to achieve the best energy efficiency class without damaging the exterior of the building. Although the procurement to select the designer took longer than planned, the procurement was successful, and the sample documentation should be finished by spring, which can be used as a basic material by other owners of buildings in the heritage conservation area when ordering renovation projects.

The pilot project will last until June, but it should already be possible to get the first answers about the Võru pilot area in the spring – how much it would cost to renovate the buildings in the pilot area to be energy-efficient and climate-neutral, how much the energy costs would be reduced as a result, what works should be done with the buildings and the related infrastructure, how cost-effective the renovation would be, how installing solar panels on roofs, for example, would affect the result, and much more besides. As a result of the pilot project, the city of Võru will figuratively be the first in the world to conduct a digital energy audit of an area, which would currently take energy auditors several months to complete – using RESTO, it should be possible to prepare it in a few hours in the future. Several other Estonian cities have already shown interest in a similar analysis.

In the context of research, RESTO has also generated a wealth of new knowledge. In the course of the project, completely new calculation models for energy efficiency and cost-optimal renovation will be developed, which must be able to perform large-scale calculations even with less accurate initial data. Finding a balance between the researchers' desire to provide the most accurate calculation results and the policy makers' desire not to wait for the databases to be organised and to receive recommendations to choose which direction to take must be possible in order to be able to propose a prototype. Despite the short duration of the project, the project team has set itself the goal of preparing at least five research articles in cooperation with other parties.

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