Thermal storage capacity describes how much heat a building material or component can absorb, store and release again after a delay. In construction, this is particularly relevant when it comes to maintaining a stable indoor climate, providing protection against summer heat and the behaviour of a component over the course of the day.

However, anyone designing or insulating building components should not consider thermal storage capacity in isolation. It is not a single parameter that is decisive, but the interplay between the material, the layered structure, the insulation and the building’s use. This is precisely where the difference lies between a theoretical material property and a solution that actually works in a building.

Why heat storage capacity is important

Components absorb heat from their surroundings and release it again as the temperature falls. How quickly this happens depends, amongst other things, on their mass, bulk density, specific heat capacity and overall structure.

In practice, this means:

• Rooms containing heat-storage components are less responsive to temperature spikes
• Lightweight structures generally heat up more quickly
• The arrangement of the layers influences how heat is retained or conducted within the component
• Well-designed insulation helps to limit heat flow in a targeted manner

This is particularly relevant when it comes to heat protection in summer. After all, it is not only the thermal mass that determines how quickly a room heats up, but also how effectively heat gain through the roof, walls or ceiling is reduced overall.

It’s not just the quantity that counts

In discussions about heat storage capacity, the focus is often placed primarily on heavy construction methods. In practice, however, this view is too narrow. Whilst it is generally true that high-density building materials can store more heat than lightweight ones, it does not automatically follow that heavy structures are always the better solution.

The key factors are the overall design of the component and the requirements that must be met. A component can only function effectively if thermal insulation, moisture protection, its design and its intended use are all properly aligned.

This is precisely why heat storage capacity should always be considered in the context of the system as a whole. A high storage mass alone is no substitute for careful design of the component.

The role of insulation

If heat is to remain on the desired side of the component for as long as possible, insulation is required to limit the flow of heat. This applies in both winter and summer.

High-quality insulation reduces heat transfer through the building element, thereby helping to maintain a more balanced temperature. It does not prevent heat from being stored, but rather influences how quickly heat enters or leaves the building element.

This is precisely why the position of the insulation is always a relevant factor when assessing thermal storage capacity. If a building element is insulated on the correct side, the existing thermal mass on the inside can be utilised more effectively. At the same time, heat gain from outside is reduced.

What this means for Switzerland

In Switzerland, summer thermal insulation is not assessed on the basis of a single material parameter, but rather on the interaction between the building component, its use and the building envelope. The requirements relating to thermal insulation, moisture protection and indoor climate are particularly important in this regard.

In terms of design, this means that it is not a single building material that determines the quality of the solution, but rather a carefully coordinated structure. This is precisely why it is worth considering the component as a whole, rather than focusing solely on individual parameters such as mass or thermal storage capacity.

What this means for SAGER Solutions

At SAGER, we do not view thermal insulation in terms of individual figures, but rather in terms of the function of the entire structure. Particularly when it comes to external walls, roofs or ceilings, the aim is to create a solution that makes sense from an energy efficiency perspective and works reliably in everyday use.

With SAGLAN glass wool insulation, SAGER offers solutions that effectively reduce heat flow and can be integrated into a variety of building component structures. The key factor here is not a single performance figure, but the contribution the insulation makes to a harmonious overall structure.

In practical terms, this means:

• Targeted reduction of heat loss in winter
• Reducing heat gain in summer
• adapt the assembly to the specific structure
• improve the performance of the component as a whole

This holistic approach is crucial, particularly in the case of buildings where summer heat protection, moisture protection and energy efficiency must be considered together.

Heat storage capacity and summer heat protection

When it comes to summer heat protection, the ability to store heat is often the subject of particularly heated debate. This is understandable, as components capable of storing heat can help to mitigate temperature spikes. At the same time, it is important to note here too that it is not just the thermal mass that determines the outcome.

Shading, ventilation, airtightness, building component design and insulation also influence the indoor climate. Anyone wishing to improve heat protection in summer should therefore not simply distinguish between ‘heavy’ and ‘light’ building materials, but assess the entire structure.

This holistic approach is particularly important in the Swiss context. This is because thermal insulation requirements can only be effectively met if the behaviour of the entire building element is taken into account.

Conclusion

Thermal mass is an important property of building materials and components. However, when planning, it is not enough to consider this value in isolation. The key factor is always the interplay between thermal mass, insulation, the layered structure and the building’s use.

That is precisely why it is worth looking at the component as a whole. After all, a solution is not considered good simply because a single parameter is impressive, but because it functions properly from a technical point of view within the building.

Would you like to improve the thermal insulation of your project in a targeted way, or choose the right construction for walls, roofs or ceilings? Then Please contact our specialist advisers. We’d be happy to help you choose a solution using SAGLAN glass wool insulation and advise you on the most suitable system configuration for your application.