Insulation against the heat in summer

To protect living spaces against heat, especially those directly under roofs, the insulation material used must have enough thermal storage capacity to ensure the flow of warmth from the exterior to the interior area is adequately dampened. Wood has a thermal storage capacity of 2100J/kg, giving it the highest capacity of any construction material.
That’s why wood insulation boards provide significantly better insulation against heat in summer than conventional insulation materials.
Thermal storage capacity refers to the ability of the insulation material, in this case wood, to absorb and retain thermal energy (technically referred to as time lag) before allowing it to reach the building’s interior in a reduced magnitude (technically referred to as decrement factor). During the night, the temperature sinks outdoors and the thermal energy is released from the exterior of the building, keeping the fluctuation of temperature at a minimum inside the building.

Example:
The time lag for GUTEX 180 mm Thermosafe-homogen insulation is 10 hours. With a temperature fluctuation of 21°C, as shown in the diagram, the temperature fluctuation of the air in the interior of the building is 3°C. (Decrement factor = 7)

What is the best way to insulate against summer heat?
Besides the usual constructional factors like location and size of the windows, air and wind tightness of the building and ventilated construction, the choice of the right insulation material is decisive.
The ideal insulation material is one that provides effective protection against cold in winter and heat in summer. GUTEX wood fibreboards perform superbly in both applications. For example, GUTEX Thermosafe-homogen boards possess a thermal conductivity coefficient of 0.04 (W/mK) and a specific heat capacity of 2100 (J/kg*K).

Thermal diffusivity is the ratio of thermal conductivity to volumetric heat capacity.

a= thermal conductivity
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specific heat capacity x density

The lower the thermal diffusivity, the better the insulation against heat in summer and cold in winter.