Old televisions become climate-friendly insulation


The climate debate is raging, and there is growing demand for each of us to consume less energy. One of the major culprits when it comes to energy waste are poorly insulated houses, and in the future, there will be greater restrictions on the materials that builders can use when they construct our homes. In this context, researchers from Aalborg University have developed a new and very robust insulation material from old televisions and CO2.

This new insulation material, called glass foam, can insulate just as well as mineral wool and is also robust enough in itself to be used as part of the supporting structure of buildings.

Compared to insulation with mineral wool, glass foam can reduce the thickness of an insulated wall by 12 to 15 centimetres and retain the same level of insulation.

- “With glass foam, we can make thinner exterior walls with the same insulation properties, or we can make walls of the same thickness with improved insulation. This makes it easier to comply with the statutory requirements for better insulation and more energy-efficient houses”, explains Martin Bonderup Østergaard, from the Department of Chemistry and Bioscience at Aalborg University. In April 2019 he defended his doctoral thesis on the subject.

glass foam is like a hard sponge made of glass and gas

Glass foam is not actually a new type of insulation material, as it is already used to insulate underground piping systems and foundations under buildings, among other things.

Glass foam can be compared to a hard sponge, in which the air holes in the glass structure are filled with a gas. This gives the insulation material highly attractive properties in terms of both insulation and structure.

However, the material has not yet become popular as the preferred insulation material for housing construction. However, it may well happen very soon.

Better for the environment to make glass foam from old cathode-ray tubes

Through his research, Martin Bonderup Østergaard has made improvements to glass foam that will make it more attractive as an insulation material. Among other things, he has studied how the glass composition and gas type affects the insulating properties of glass foam.

Part of his research shows that cathode-ray tube (CRT) glass from old televisions gives the glass foam particularly good insulating properties, while CO2 also insulates extremely well.

CRT glass has a lower thermal conductivity than e.g. window glass, while CO2 is better than ordinary atmospheric air at keeping heat trapped in, as heat does not pass through CO2 as easily.

- “There is an environmental perspective when it comes to recycling old CRT as insulation for houses. One of my colleagues did some calculations that revealed that we currently have enough old CRT to insulate with our form of glass foam for many years to come”, says Martin Bonderup Østergaard.

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