Behind the numbers - How sustainable is stone wool?

SUSTAINABILITY 29/12/2020

Stone wool is a fire-safe and durable insulation material that enables energy-efficient building. In terms of the environmental impact of stone wool, it is the 1:200 ratio that comes up almost always. What does it actually mean?

The world of responsibility is built on numbers. More specifically, it is built on years and percentages that measure the joint effort to overcome climate change. Those numbers can be quite harsh.

In EU, buildings are responsible for approximately 40% of the total energy consumption of EU. Buildings also account for more than third of the greenhouse gas emissions. For example, in Finland, CFCI (The Confederation of Finnish Construction Industries) has calculated that built environment generates annually 17.1 million tonnes of carbon dioxide. This is much more than, for example, transport generates.

However, there are better or somewhat more optimistic numbers. The EU has set an objective for Europe to be the first climate-neutral continent by 2050. The plan is to at least reduce the emissions by half by 2030.

Owens Corning Paroc is committed to this goal.

There is one other number essential to these objectives. The 1:200 ratio. This encapsulates what is vital: for each tonne of CO2 generated in the manufacturing of stone wool, about 200 tonnes of CO2 is saved over a 50-year period. That is how much insulation improves the energy efficiency of buildings.

The numbers 1 and 200 are both important in terms of climate change.

Stone wool is a climate shield

Let’s begin with the bigger part of the ratio, the number 200. According to many experts, it is crucial in working towards meeting the objective of a climate-neutral Europe.

Mineral wool, such as PAROC® stone wool, is the most widely used insulation material in Europe. Owens Corning Paroc’s materials are trusted because they are fire-safe, durable, reusable, sound-absorbing as well as moisture-resistant.

They create a climate shield that envelops the building walls and roofs thus radically reducing the energy needed for heating, cooling and use.

The word ‘radical’ might, at first, sound like an exaggeration but the numbers speak for themselves. Eurima (The European Insulation Manufacturers Association) refers to a study by Material Economics, that 85% of the greenhouse emissions generated by the European building stock comes from the energy needed for heating, cooling and use. With better insulation, the buildings would consume considerably less energy and would generate considerably less emissions.

The great news is that we are well on track in this area with new buildings and those built in the recent years. In a number of countries such as Finland and Sweden, new buildings must meet strict criteria regarding energy efficiency.

But, not all houses in Europe are new. The European Commission has calculated that 85% of the buildings in the EU were built over 20 years ago when energy efficiency requirements were not as tight as today. This means there are millions upon millions of houses with energy escaping through the roofs and walls.

Fortunately, the solution is right there in front of us: renovation of old buildings and retrofitting the insulation to meet today’s needs with durable, high-quality insulation material.

The European Commission unveiled its Renovation Wave Strategy in October 2020. The vast strategy aims to double renovation rates and, among other things, ensure that renovations lead to better energy efficiency.

Investment as well as incentives are needed. Eurima states in it’s position paper that if the renovation of old buildings in Europe would remain at the current one percent annual rate, it would take a century for the built environment to achieve carbon neutrality.

Owens Corning Paroc wants to minimize its own footprint

What about the other number in the ratio, number one, indicating the amount of carbon dioxide generated by the production of stone wool currently? Is it really something worth thinking about since the advantages outweigh the disadvantages several times over? Each PAROC® insulation slab is part of the solution in fighting climate change.

“Of course it is”, says Beatrice Hallén, Sustainability Leader at Owens Corning Insulation Europe and Paroc.

”As soon as we achieve halving that number one, the ratio of manufacturing of stone wool and saving emissions already becomes 1:400. We are persistently working in order to make our manufacturing process as low-carbon as possible. We believe each act makes a difference in fighting climate change.”

A good example of such an act is PAROC® Natura, a carbon neutral stone wool insulation product set to be available in the beginning of 2021.

It is manufactured using low-carbon melting technology, green electricity, reused waste material and new technologies. Then, by compensating the remaining CO22, Owens Corning Paroc has created a totally carbon neutral insulation product.

There is nothing like stone wool

Stone wool is produced in an energy-intensive process which, depending on fuel and technology, releases CO2 during the manufacturing. In the perspective of the carbon footprint of a complete building the impact of different insulation materials is very limited, but nonetheless Owens Corning Paroc wants to bring the numbers down.

So, what does it take to halve the emissions generated by the manufacturing of mineral wool and, finally, to eradicate the emissions?

First and foremost, it requires investing in new technology and circular economy, believes Mats Björs, CEO at Swedisol (Trade Association for Leading Mineral Wool Insulation Manufacturers in Sweden).

“Compared with competing materials, mineral wool has an advantage because it can be recycled and used in so many different ways. Other insulation materials such as wood fiber insulation and plastic insulation can only be recycled by burning and recovering the energy. The development of a circular economy is wonderful for mineral wool insulation.”

Björs’ thoughts are in line with the famous quote from French President Emmanuel Macron that sometimes, when making choices, you have to be able to think simultaneously about more than just two things – or a couple of numbers.

”Stone wool is an excellent insulation material that makes buildings not only extremely energy-efficient but also fire-safe. This is unique for stone wool. Furthermore, with the minimization of manufacturing emissions, stone wool is, by any measure, practically unbeatable.”


Pekka Vuorinen, Director, Environment & Energy, of The Confederation of Finnish Construction Industries was also interviewed for this article.