Hot summer days often result or end in suffering due to uncomfortable temperatures in the loft. A simulation and real-life experiment have proven that room temperature can be improved by up to ~7°C through dynamic insulation, i. e. combining insulation with DuPont™ Energain® phase change material.
The roof of a building not only needs to protect against cold, wind and rain but also against heat. If insufficiently insulated, a roof can quickly become a source of energy loss or heat gain of the building.
During hot summer days, the external roof temperature can reach up to 85°C1 with the majority of the heat blocked by the tiles. However, some heat may penetrate this layer and warm up the loft depending on the insulation product and/or its thickness for example.
U-values² for roof applications range from 0.2 up to 0.1 W/m²K for passive house standard, resulting in thick insulation layers of up to 200 mm and more, depending on the selected insulation product. The applied insulation can significantly impact the loft temperature.
But even with excellent insulation, temperature in the loft can rise far above comfortable room climate levels. Creating a dynamic insulation system through the combination of traditional insulation products as for example glass fiber with Energain® thermal mass panel can help to significantly improve the room climate during the summer months (as shown in diagram). The simulation showed that the attenuation effect thanks to Energain® ranges from 5.5 to 8°C for the same insulation thickness of glass fiber with a thermal conductivity of 40 mW/m.K.
Diagram Dynamic (Glass fiber and Energain®) vs. traditional (glass fiber, 40 mW/m.K) on internal loft temperature, Source DuPont simulation
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1 K. Liersch: Belüftete Dach- und Wandkonstruktionen, Band 3 – Dächer, Bauphysikalische Grundlagen des Wärme- und Feuchteschutzes,
2 U-value: Thermal transmittance - Measure of the rate of conductive heat loss of a building element or component