Heat Stress App

With the Heat Stress App, estimations can be made regarding the effectiveness of adaptive measures.  Also, it is divided into two parts:

a) The building tool, which is used to qualitatively assess the heat load of indoor spaces in residential buildings and the effectiveness of various adaptation measures.

b) The open space tool allows an orientating, quantitative assessment of the effectiveness of adaptation measures in open urban space. The impact on human thermal well-being is assessed with a bioclimatic index. In addition, effects on biodiversity and carbon storage are described qualitatively.


a) The Building Tool


... is used for a first qualitative assessment of the overheating risk of indoor spaces in residential buildings as well as the effectiveness of various adaptation measures and is designed to be very simple and user-friendly. For this purpose, based on thermal building simulations carried out in the HeatResilientCity project, the current heat load of a room is first assessed in a five-stage traffic light system.

For this purpose, the location of the room in the building (floor and window orientation), the size of the windows, the construction of the flat and the possibilities for window ventilation must be specified in the tool.

In the second step, the adaptation measure to be evaluated, such as external sun protection or green roof, must be selected in the tool. The effectiveness of the measure on the overheating risk in the room under consideration is shown by the change in the five-stage traffic light (see figure). Thus, an initial assessment of the heat load of indoor spaces as well as the effectiveness of adaptation measures can be done in a very quick and simple way.

It is important to mention that the building tool does not replace the detailed analysis of the overheating intensity in buildings by means of detailed observations, e.g. by means of building simulations. It only serves as an initial evaluation.


b) The Open Space Tool


... is based on urban climate simulations with the established microscale climate model ENVI-met. Due to its high spatial resolution, a detailed mapping of the model to reality is possible. With the open space indicator, the evaluation of adaptation measures is possible for different summer months as well as times of day and night. This possibility of temporal differentiation in the evaluation of adaptation measures is another innovative feature compared to existing tools.

The open space indicator is based on extracted model areas that can represent different adaptation measures and states. Care was taken to reflect a variety of surface characteristics (e.g. tree areas, sealed area, different proportions of tree and meadow) and roads of different orientations were chosen to address as many scenarios as possible.

How effective a possible adaptation measure is in terms of reducing heat stress is shown by a comparison between the selected baseline condition and the selected adaptation measure for both the open space indicator and the building tool. A traffic light system quickly makes clear how effective a measure is.

In addition, effects of ecosystem services of the baseline area and the area with adaptations are assessed, such as recreational value, nature experience, bio-diversity, and carbon storage.

The tool was developed in cooperation with the Technical University of Dresden (Chair of Meteorology) and the Leibniz Institute for Ecological Spatial Development (IOER) in the joint project "HeatResilientCity".