Gå til hovedindhold

Circular Renovation

Denne idé er en del af The Circular Construction Challenge – Rethink Waste

Jørgen Lange
Jørgen Lange
4. oktober 2018

Today’s renovation projects are mainly focusing on solving the energy efficiency challenge. The circular construction is the next challenge to reach the goals of zero emission in the building sector and to secure a sustainable use of resources.  

The idea of the “Circular Renovation Project” is to focus on circular construction elements in the energy renovation process to be more biobased, circular, and with reused materials and construction methods.

A typical energy renovation project involves the following:

  • Insulation and improvements of the building envelope
  • Ventilation
  • Energy supply by renewable energy sources

The EU-project proposal, HESTIA, Stimulation of Large-Scale Deep Energy Renovation in Residential Buildings is focusing on innovative, biobased solutions for energy renovation. The Danish partners have tried to strengthen the focus on the use of resources and materials in the energy renovation process, but has not succeeded. Therefore, the Circular Construction Challenge will be of great value to develop this side of the energy renovation process.

We have a team consisting of consultants, producers and end users in the HESTIA project, of which we have selected the following for the “Circular Renovation Project”:

  • Thermal and acoustic materials using waste by CTCON, Spain
  • Biobased tubes and sheets, double layer panels and K-box for the pipes of HVAC systems, PVs, Solar Panels by K-FLEX, Poland
  • MicroVent by InVentilate, Denmark
  • ClimateCover – roof with building Integrated PV by Komproment, Denmark

Our case in HESTIA is in Avedöre Social Housing Company, and this case can also be activated within the “Circular Renovation Project” with the possibility of showcasing a demonstration of “Rethink Waste”.


In the Circular Economy Building Process (see below - illustration from “Det byggede Danmark” by Boligøkonomisk Videncenter, 2016), the ”Green City Circular Renovation” project focus on the reuse of (raw)materials (waste), how to integrate the reuse in the design, the overall integration of reused materials in the renovation process and how the materials can be reused in new renovation projects.

The products of the selected companies has been through an initial product development, but there is a wish for further development within materials and optimization of the use of resources. Thus, this gives a consolidated organizational and technical possibility for developing a successful prototype of the “Circular Renovation Project”.

Reuse of raw materials are integrated in the production process of the thermal and acoustic materials from CTCON, Spain, using waste materials in form of concrete, creating new panels for insulation and improved acoustics.

K-FLEX makes biobased tubes and sheets, double layer panels and K-box for the pipes of HVAC systems, PVs and Solar Panels from bio based polyurethane and compact rubber. All the elements can easily be removed and recycled. Reuse of waste materials e.g. rubber is a potential to be investigated.

InVentilate’s MicroVent system has the lowest electricity consumption on the market for ventilation systems. The system use recyclable materials. Potential for employment of biobased materials can be investigated.

ClimateCover by Komproment is a PV roof and façade solution that incorporates natural slate and solar cells. It is especially suitable for renovation. The natural slates are reusable. Komproment has a Cradle to Cradle certification for another material: tile shavings – a new material for facades with the characteristics of tiles but only 14 mm thick. The tile shavings are delivered as a complete system solution and are manufactured in seven colors and with three different surface structures.

A more detailed description of the products can be found enclosed.


The visionary aim of the ”Circular Renovation Project” is to find products for the energy renovation, which can be developed concerning use of materials and – in continuation of the Circular Construction Challenge - can obtain a cradle to cradle certification or description. In the current situation, it is a challenge for the building owners, the consultants, architects and engineers to find solutions for the energy renovation that are well described and focus on the circular thinking. The ” Circular Renovation Project” aims at finding the products and integrating them in the energy renovation including getting the acceptance of the users and empower their behavior in managing the solutions.

Value creation

The main value will be the demonstration of the possibilities of reduction of the carbon footprint and to secure the sustainable use of resources in future energy renovation projects.

The value, the users will get, is the quality and comfort of living in a house that is energy renovated with a particular low carbon footprint. As the renovation will be a demonstration of the actual possibilities of a circular renovation, the users will also be empowered to manage the improved and smarter solutions. Not to be underestimated is also getting ownership to a project of public interest and the opportunity of informing other users of their experiences.

As the project involves companies from Denmark as well as other European countries, the results can lead to more export for Danish, Spanish and Polish companies and dissemination of the knowledge in a European context.

The UN Sustainable Development Goals, we try to meet, are no. 6, 7, 8, 9, 10, 11, 12, 13, 16 and 17 


An estimated 97% of the EU’s building stock (corresponding to close to 30 billion m2) is considered energy inefficient, while up to 75-85% of it will continue to be utilized in 2050. Additionally, buildings (both residential and non-residential) consume 40% of the EU’s final energy demand, i.e. more than any other sector in EU, and are responsible for approximately 36% of all CO2 emissions in the Union. According to data from the EU building stock observatory, around 77% of the residential buildings in EU have been constructed before 1990 and roughly 11% of Europe’s population still experiences energy poverty due to poor building quality, especially thermal efficiency. According to the Commission’s impact assessment, renovation would be needed at an average rate of 3% annually to accomplish the Union’s energy efficiency ambitions in a cost effective manner, but with current renovation rates (0.4-1.2% depending on the country) it will take more than 100 years to renovate all the EU building stock.

As a consequence, the project will have a vast potential for upscaling the sale of circular products on the European energy renovation market.


Apart from the producers, mentioned above, EKOLAB ApS, a consulting engineering company and European Green Cities ApS, a network of cities, organizations and companies working for green urban development in a sustainable Europe and coordinator of innovation projects in Avedöre Boligselskab, will participate.

The ” Circular Renovation Project” aims at demonstrating the circular renovation in Avedöre South.

Avedöre South (AS) is a Social Housing Company, one of three in Avedöre Stationsby. AS stands in front of a deep renovation in 2019-2020. The building is used for residential purposes. It has 1.028 flats and is the longest building in Denmark (1.475 m long). A general rehabilitation of Avedöre South and the energy supply system is under planning and will be financed by the National Building Fund and Avedöre District Heating Association. The tenants of AS are very engaged in changing the identity of the area from the label of being socially deprived to being green and sustainable. It will be possible to integrate a test of the “Circular Renovation Project” in the general renovation project in AS.

The team is open for more partners and solutions, a selection of products and focus on the use of resources.

Enclosed a description of the products, their status and potential. 

With kind regards

Jørgen Lange

Ekolab ApS
Vestergade 48 H, 2.tv.
DK-8000 Aarhus C
Tel.: +45 8613 2016
CVR no.:   31 76 65 91


Elsebeth Terkelsen

European Green Cities ApS
Norsgade 17
DK-8000 Aarhus C

Tel.: +45 2757 1955

CVR no.: