Thermal insulation

Thermal insulation with CLTPLUS?
It works.

The thermal insulation of buildings is a crucial aspect of building climate planning and construction. The minimum requirements aim to minimise a building’s energy consumption in summer and winter while providing thermal comfort and protection against extreme temperatures.

The U-value, also known as the thermal transmittance
coefficient, measures the ability of a component to conduct and transfer heat.

CLTPLUS is calculated with an average wood moisture content of 12% and a thermal conductivity of 0.12 W/m²K in accordance with EN ISO 10456.

Operating principle

WINTER THERMAL INSULATION

Based on an unclad CLTPLUS external wall with a thickness of 100 mm and taking into account the internal and external heat transfer resistance, the following values are obtained: U=0.997 W/m²k, phase shift 5.5h. If the U-value of a CLTPLUS solid wood panel insulated with mineral wool with a thickness of 160 mm and a thermal conductivity of 0.035 is calculated, the following results are obtained: 100 mm CLT+160 mm mineral wool:
U-value = 0.179 W/m²k, phase shift = 9.5h

SUMMER HEAT INSULATION
(PHASE SHIFT)

One of the most important advantages of solid wood construction is the higher phase shift. The phase shift describes the time it takes for the temperature on the cold side of a component to increase by 1°C. The higher the phase shift, the longer it takes for heat to penetrate from the outside to the inside. Ideally, the phase shift should be longer than 12 hours, as then the building does not heat up during the day and the external components can cool down again at night.

How it works

Due to the higher mass of the solid timber elements, solid timber construction achieves a higher phase shift than timber frame construction. This favours thermal insulation in summer, as the building takes longer to warm up and the interior therefore remains cooler. In addition, solid wood has a higher heat storage capacity than other building materials, such as concrete or brick. This means that solid wood is able to absorb and release heat when the ambient temperature drops. Thanks to this property, solid wood can help to keep the building cooler in summer and warmer in winter.

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Building physics