Thermal Imaging: Picture the Invisible


Visualising heat loss and becoming more thermally aware could engender a greater understanding of energy consumption and of everyday heat loss from buildings.

By making the invisible aspects of familiar surroundings visible, can we have a more compelling effect upon our behaviour and the way that we relate to energy usage?

Working with Dr Grant Wilson from Chemical and Biological Engineering, who has previously worked on a similar project for Festival of the Mind, we captured images of six buildings from around our University campus. The project aims to raise public awareness of heat loss and energy consumption by presenting the topic in a visually stimulating and captivating way.


Flicking a light switch or turning up the heating have effects which we as individuals can directly experience. Our inability to see or feel the energy itself used for these actions, other than via its end result, makes its everyday occurrence difficult to relate to. Whilst we may be aware of having the heating on, we are less tuned in to the constant energy transfer and the possibility of heat leaking from our buildings.

The heat escaping from the open windows in the Arts Tower capture may have been prevented if one could visualise what was being lost.


What is thermal imaging?

Infrared radiation cannot be detected by the human eye, having longer wavelengths than visible radiation on the electromagnetic spectrum. An infrared, or thermal imaging, camera detects infrared radiation emitted from the objects it is focused upon. The device then produces an image called a thermogram which is then transferred onto the camera screen. The thermogram is a measure of the surface temperature of the object as a thermal imaging device displays the amount of infrared energy emitted, transmitted and reflected by the object. The amount of radiation emitted by an object increases with temperature, meaning we are able to view temperature variation.

What is it used for?

Thermal imaging is commonly used to detect heat leaks in homes and buildings to improve building efficiency. By focusing a thermal imaging device upon a pipe or by looking at the roof of a home, users are able to detect where heat is leaking from.

This project aims to illustrate what heat looks like, in order to raise public awareness into energy consumption and to provide us with a new perspective to view our surroundings.


These images were captured on a 320 x 240 pixel thermal imaging camera, captured in overlapping stages and stitched together using specially designed software. The stitching tool make it possible to create images would could not normally have been produced on a device of this resolution. Grant developed this software for a previous project, working with Festival of the Mind to showcase thermal images of Sheffield’s well-known buildings.


As a thermal imaging device detects infrared radiation on an objects surface, it is important to capture the images in favourable conditions. Adverse weather conditions can skew the results achieved with the camera. Too much wind can enhance heat transfer from the surface of the object, thereby reducing surface temperature. Rain droplets on an objects surface or moisture in the air will affect the camera’s reading whilst air temperature will also influence results. Taking this into account, the images of our University buildings were captured on an evening in early February 2015. There was no precipitation, low wind and an air temperature of around -1 degree Celsius.

External effects are visible on this image of the Amy Johnson building, where the sunlight shining directly onto the building’s surface has caused a high temperature reading when contrasted to the part of the building which remains in shadow.


The visual presentation of energy is a powerful communication tool and can demonstrate in an interesting and emotive way important information surrounding energy consumption. By looking at our University campus in a new way, we can transfer this visual representation of heat loss onto our everyday knowledge of our surroundings, triggering thoughts about energy usage.

By presenting this issue in a visually stimulating way, we hope to increase engagement with the topic of energy consumption. Around 70% of global carbon emissions come from cities and in the UK, around one third of our greenhouse gas emissions result from buildings. Raising public awareness and engendering interest in this topic can only be beneficial to drawing attention to and environmental concerns.

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