Lighthouse City Helsinki launches tool to visualise heat losses in buildings

“Kattohukka”, a building heat loss visualisation tool, was launched in April 2018 as part of the Helsinki Urban Platform, a collection of smart city related data and services. It is an easy-to-use web based service that visualises thermal losses from the buildings in Helsinki. The heat loss map is an open data interface, and the service is available to everyone.

Kattohukka features a thermographic map acquired on a clear, cold winter night. The map represents the surface thermal radiation measured from each roof using a thermal imaging camera. However, the thermal radiation visual itself does not directly represent the roof insulation quality of the building. To interpret the thermal image colours in terms of roof insulation, one must consider factors such as possible solar panels on the roof, the material and shape of the roof and whether the space below the roof is heated in winter or not, which all have an effect on the thermal image.  

In Kattohukka, the user has to answer these four questions, after which he can see a legend explaining the colours in terms of roof insulation quality.  In the case that the user is not familiar with the roof properties, he can still look at the relative colour differences of the roof for possible heat loss sources. The user can also switch the view from thermographic map to an aerial image to check the details of a roof. The service can be used by property owners as well as companies when planning renovations.  

The web page also includes information on building heat losses and tips how to improve energy efficiency. Kattohukka was designed by the Helsinki Region Environmental Services Authority HSY and implemented by Kairo Design Agency Ltd.

The tool Kattohukka (in Finnish) can be found at