Domen Ivanšek, Head of Building Science for Knauf Insulation, looks at how we can unleash the full potential of insulation as a year-round protector against an increasingly extreme climate. Here, Domen explains that by rethinking building design and choosing products wisely, we can make insulation do more and ultimately achieve climate-resilience.
It’s no secret that our climate is changing. Rising temperatures, combined with an ageing population, have made us more vulnerable to the threat of overheating and that will only increase over the coming years. In fact it’s predicted that, without mitigation, extreme heat will impact 300 million Europeans each year by 2100, resulting in 90,000 fatalities.
We spend around 90% of our time indoors, so buildings have a significant impact on our health and wellbeing. That’s why it’s critical that our industry pulls together to make every single building (both new and existing) climate-resilient – and we need to start now because the changes we make today will be felt for decades to come. For example, in the UK, 80% of the buildings that will be occupied in 2050 are already being built and renovated today, so there’s really no time to waste.
Current legislation is focussed on keeping buildings warm in winter and insulation plays a central role in achieving that. But with the right design, construction, renovation and maintenance, buildings can protect us from extreme temperatures all year round.
Climate-resilient design
Climate-resilient buildings require a holistic approach, considering all aspects of the construction. The key is to create a stable, controllable internal environment, which enables heating and cooling systems to work effectively and economically.
This approach might include considering the orientation of the building, in relation to wind and peak sunlight, or optimising glazing and shading so that solar heat gain is balanced throughout the seasons.
It could also mean managing internal heat gains, for example by insulating elements like hot water pipes, and installing energy efficient appliances, to ensure neither contributes to unwanted heat within the building.
Ventilation and airtightness are also key factors to consider. Carefully managed ventilation within an appropriately airtight building will allow for greater control over the internal temperature.
The right insulation, correctly installed, will then reduce unwanted heat transfer, stabilising the internal environment and protecting occupants from the effects of external heat or cold. Adopting these principles means you can make insulation do more – it can provide that protection not just in winter but throughout the year.
Getting the insulation right
The two factors to prioritise when specifying insulation for thermal comfort are its R-value and real-world performance.
In terms of protection against overheating, there is negligible difference between insulation products with different densities and heat capacities. The R-value however, is important because it indicates the insulation’s ability to resist the transfer of heat. The higher the R-value, the higher the thermal resistance… at least on paper. Unfortunately, some products are more difficult to install correctly than others, under real-world site conditions. For example, if a wall’s surface is not perfectly uniform, rigid board insulation won’t sit flush against it. This can lead to air gaps, which compromise thermal performance.
This difference between designed and real-world performance is known as the ‘performance gap’ and it has the potential to de-stabilise the internal building environment that thermal comfort relies on.
To help prevent this, it’s important to specify materials which are ‘buildable’. Mineral wool insulation, for example, has a flexible nature which adapts to minor imperfections in the substrate. Its fibrous surfaces also friction fit tightly together, all of which minimises air gaps and maximises performance. And because it uses trapped air for insulation, its thermal performance doesn’t degrade over time, like that of some other insulants. Essentially, mineral wool is easier to ‘get right’, making it a reliable choice for providing a building’s passive protection.