The lambda value (λ-value) is a key measurement in determining the thermal conductivity of an insulation membrane. Understanding this value is crucial for choosing the right membrane for your project, as it directly affects how well the material can prevent heat loss. In this article, we’ll explain what the lambda value is, why it matters, and how it influences energy efficiency in buildings.
What is the lambda value?
The lambda value, also known as the thermal conductivity value, indicates how well a material can conduct heat. It is measured in watts per metre per degree Celsius (W/m·K). Essentially, the lower the lambda value, the better the insulation membrane is at resisting heat flow. For example, materials with a low lambda value will prevent heat from escaping in winter or entering in summer, making them more effective at insulating your home or building.
Why is the lambda value important in insulation?
The lambda value plays a significant role in determining how energy-efficient an insulation membrane is. The lower the lambda value, the less heat will pass through the membrane, which helps reduce energy consumption and costs. Choosing membranes with a low lambda value is especially important in projects where high thermal performance is required, such as energy-efficient buildings.
For instance, high-quality insulation membranes like vapour control membranes have low lambda values, making them an excellent choice for maintaining optimal thermal efficiency. The lambda value helps you compare different membrane options, enabling you to select the most suitable product for your specific needs.
How is the lambda value measured?
The lambda value is measured under controlled conditions, typically in a laboratory, where the material’s thermal conductivity is tested. The result is a value expressed in W/m·K, showing how much heat passes through one square metre of the material for every degree Celsius of temperature difference. The lower the value, the better the material is at insulating.
Factors affecting the lambda value
1. Material composition
Different insulation membranes have different thermal conductivities, and their composition significantly affects their lambda value. For example, vapour barrier membranes and vapour control membranes each have unique lambda values, offering specific benefits depending on the application. Choosing a membrane with a low lambda value ensures better thermal resistance and insulation performance.
2. Density of the membrane
The density of an insulation membrane can impact its lambda value. Generally, denser materials allow more heat to pass through, increasing the lambda value. However, advanced insulation membrane technologies can achieve low lambda values while maintaining lighter weights. It’s important to compare both the lambda value and the membrane’s density when selecting the best product for your project.
3. Moisture content
Moisture can negatively affect the lambda value of insulation membranes. Wet membranes conduct heat more easily, increasing the lambda value and reducing the material’s effectiveness. This is why it’s essential to protect your insulation membrane with a proper vapour barrier to prevent moisture build-up and maintain optimal thermal performance.
How to choose insulation membranes based on the lambda value
When selecting insulation membranes, aim for materials with the lowest possible lambda value to improve the thermal efficiency of your building. Products like insulation membranes offer excellent thermal performance due to their low lambda values. Keep in mind that lower lambda values often mean that you can achieve the same thermal resistance with a thinner material, providing flexibility in design.
What you should remember
The lambda value is a critical factor in determining the thermal conductivity of insulation membranes. Choosing products with low lambda values ensures better energy efficiency, reduced heat loss, and lower energy costs for your building. By understanding how the lambda value works and selecting the right membrane for your project, you can significantly enhance the thermal performance of your home or building.
For a wide range of high-performance insulation membranes and vapour control solutions, visit MG Bouw. We offer top-quality materials that help you achieve the best thermal performance for any construction project.
