Project Overview

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The project runs from February 2020 till ultimo 2022


The project is supported by the philanthropic association Realdania. It involves nine partners covering the entire range from data gathering and development to implementation and dissemination. The project is coordinated by Danish Technological Institute. Read more about each of the partners and their contribution to the project through the list of project partners.


In recent years, the establishment of green walls on facades has become increasingly popular in cities. Green walls enable a greener townscape where horizontal planting is not possible. Nonetheless, the "small" thermal mass in a plant wall causes the wall to be more easily heated or cooled by the sun, air, and precipitation. Therefore, the plants will experience more and greater temperature fluctuations than plants in terrain – both when it is hot, but also in winter and in early spring, when the weather can change between thaw and frost. The plants may experience more extreme and varying conditions as stress, which affects their growth.

In this project, it is examined whether the growth conditions in a green wall can be improved by reducing fluctuations and, thus, achieving conditions that better mimic the growth conditions in terrain.


The aim of this project is to create a new concept for the establishment of green walls, which examines whether the growing conditions of a plant wall can be optimized by mimicking the conditions of terrain in terms of soil temperature.

This is done by combining the green wall with a heat pump that produces, for example, hot domestic water (the concept can be adapted to the heating needs that may be – e.g. comfort heating). The heat pump then cools the green wall, so that the plants do not wake up until the season allows it, and not when the wall is simply heated by the sun.

Through this new concept, green walls are further adapted and optimized to the changing weather of northern Europe. 

Goal and the expected outcome of the project

The goal is to promote healthy, efficient, and sustainable construction and, thereby, promote better housing environments. Therefore, the project will develop a technological solution that incorporates the known technologies of green walls and heat pumps. A combination of the two technologies enables a technical solution that facilitates the dissemination and optimization of the establishment of green walls in residential areas. 

The outputs of the project are, therefore:

  • Tested and validated technology for a combined green wall/energy solution.
  • Blueprint for a system solution that can be set up by different end-users - e.g., housing associations.
  • A dimensioning tool for the correct establishment of the new technology based on requirements and available areas.
  • Potential map – mapping of Europe that shows where the new technology is best implemented.