Summer heat protection is becoming increasingly important in construction. Rising temperatures and more frequent hot days are placing new demands on buildings. In addition to traditional thermal insulation in winter, it is now increasingly important to keep rooms pleasantly cool in summer, if possible without additional cooling.

It is often underestimated that insulation can do more than just reduce heat loss. It also plays a key role in protecting against overheating.

Thinking about heat protection in summer at an early stage not only improves comfort, but also creates better conditions for a permanently balanced indoor climate.

What happens when it's hot in the building?

In summer, solar radiation acts on the roof and façade. Without suitable measures, heat penetrates the building and increases the interior temperature. This effect can increase significantly, particularly during longer periods of heat, and noticeably affect indoor comfort.

The decisive factor here is not only how much heat gets into the building, but also how much:

• How quickly components heat up
• how quickly heat is transferred
• how long temperature peaks last in the interior

These relationships are often described under the term heat storage capacity. In practice, however, it is important to realise that it is not a single parameter that determines heat protection in summer, but the interaction of all components and influencing factors.

Heat storage capacity clearly categorised

The heat storage capacity describes how much heat a material can absorb and release again with a time delay. This is an important aspect because it allows temperature peaks to be postponed.

It is often simplistically deduced from this that heavy building materials generally offer better heat protection in summer. In practice, however, this approach falls short.

The decisive factor is not a single material, but the behaviour of the entire component. In addition to the storage capacity, the layer structure, the insulating effect and the design also play an important role.

The decisive factor is the interaction

Effective summer heat protection is the result of the interaction of several factors. Only when these points are considered together is a solution created that is truly convincing in practice:

• Insulation of the building envelope
• Structural design of the components
• Airtightness
• Shading
• Use and ventilation behaviour

Aspects such as airtightness and ventilation have an additional influence on the indoor climate and are discussed in the Contribution to airtightness and ventilation dealt with in depth.

Role of insulation in summer

Insulation materials reduce the heat flow through the building envelope and thus slow down the entry of heat into the building. This reduces temperature peaks and keeps interiors pleasantly cool for longer. This effect is particularly noticeable on hot summer days. Effective insulation ensures that rooms heat up less quickly and temperature fluctuations are better cushioned.

In concrete terms, this means

• Less rapid heating of the rooms
• Reduced temperature peaks
• More stable indoor climate over the course of the day

We show how modern insulation materials are constructed and which properties play a role in this in the Contribution to the composition of glass wool.

Why "heavy mass" is not the only decisive factor

Heavy materials can store heat and release it again with a time delay. However, this property alone is not enough to reliably prevent overheating.

Because:

• Lightweight constructions can also be very effective
• Insulation materials influence the speed of heat input
• the entire component structure determines the effect

Glass wool is characterised by very low thermal conductivity and therefore reduces the heat input at the building envelope. In combination with a harmonised structure, it makes a significant contribution to effective heat protection in summer. It is therefore particularly evident in the planning stage that it is not the largest mass alone that is decisive, but the question of how well an entire building component keeps out, delays and controls heat.

Swiss requirements: SIA 180

Requirements for thermal insulation in summer are defined in Switzerland in SIA 180 "Thermal insulation, moisture protection and indoor climate".

The aim is to limit the overheating of rooms and ensure a comfortable indoor climate. Summer thermal insulation is always considered in conjunction with the entire building envelope. This shows that individual materials should not be considered in isolation, but rather the interaction of all relevant factors.

System solutions make the difference

In practice, it is clear that individual measures are rarely enough. Only coordinated systems provide effective protection against overheating in summer.

Particularly in the façade area, construction, insulation and structure have a decisive influence on the behaviour of a building. Coordinating these elements not only improves heat protection, but also creates greater safety in planning and construction. We show how such solutions are implemented in practice in the Contribution to our façade systems.

Conclusion

Summer heat protection is more than just mass. The decisive factor is the interaction between insulation, structure and utilisation.

High-quality insulation effectively reduces the heat input and forms the basis for a pleasant indoor climate - in winter and summer alike. Those who plan buildings holistically create more comfort in the long term, improve the quality of use and reduce the need for additional cooling.

Would you like to specifically improve the summer heat protection of your project? Our specialist advisors support you in finding the right system solution.