The insulation industry has its own distinct jargon with terms, whether specific to insulation materials or not, that are not immediately obvious to everyone. For example, consider the terms Rd value and Rc value. The Rd value refers to the thermal resistance of insulation material, indicating how well the material blocks heat. The Rc value, on the other hand, is the total thermal resistance of a structure, including all layers of insulation and other materials. Another common term is lambda value, which indicates how well a material conducts heat. Understanding these terms is essential when choosing and applying insulation materials for optimal energy efficiency and comfort in buildings.
What is the significance of the lambda value?
The lambda value, also known as the thermal conductivity, indicates the degree to which a material conducts heat. This value is expressed by the Greek letter λ. The concept of lambda value is applied to measure how many watts of energy pass through one square meter of material one meter thick, at a temperature difference of one degree Kelvin between the two outer sides.
By looking at this thermal conductivity, we can determine how well or poorly a material insulates. This plays a crucial role in the design and construction of buildings and other structures, where thermal insulation is of great importance. A low lambda value indicates good insulation, while a high value indicates that the material is less efficient at retaining heat.
Understanding the lambda value allows us to make informed decisions when selecting materials for insulation purposes. In this way, we can create energy-efficient solutions and contribute to a more sustainable future.
High or low lambda value
The lambda value, also called thermal conductivity, is expressed in watts per meter in degrees Kelvin (W/mk). This value indicates how efficiently a material conducts heat. A higher value, such as 10.6 W/mk, indicates that the material can conduct heat very well and quickly. On the other hand, a lower value, say 0.031 W/mk, indicates poorer thermal conductivity.
When we talk about insulation material, the very idea is to conduct heat as little as possible. Therefore, a good insulation material has a low lambda value. This means that the material has a high insulating capacity. In other words, it lets little heat through and keeps heat in during the winter and out during the summer.
Remember: the lower the lambda value, the greater the insulating capacity of the material. Materials with the lowest lambda values thus offer the very best insulation.
Materials and their lambda value
Every material basically has a certain ability to conduct heat and thus has a lambda value. For example, metals, wood, glass, concrete, etc. all have a lambda value. Gold, for example, like almost all other metals, has very good thermal conductivity and thus a high lambda value. Therefore, metals have very poor insulating properties. Liquids and gases also have their own lambda values. And in view of their insulating capacity, the latter category is especially interesting.
Still air, which is a gas, is widely used in insulation materials because of its unique properties. Indeed, it is precisely this air that provides the strong insulating factor. Air is trapped in the cells of insulation materials, such as PIR boards or XPS, which consist of compressed plastic foams. These materials have a closed cell structure in which the air, or a stationary gas, is stationary. Thanks to this stagnant air, an excellent insulating effect is achieved.
The insulating properties of materials are of great importance in the design and construction of energy-efficient buildings. Choosing the right insulation materials can reduce heat loss and save energy. Understanding the lambda value and using insulation materials with good insulating performance is essential for creating comfortable and sustainable living environments.
Lambda value and Rd value
In the insulation world, there are several terms that indicate how well a material insulates. One of these terms is the Rd value, which stands for thermal resistance. The Rd value indicates how well an insulation material of a given thickness insulates. It is an important measure for assessing the insulating capacity of a material.
Unlike the lambda value, where a lower value is better, a higher Rd value means better insulation capacity. This is because the Rd value divides the thickness of the material by the lambda value. The higher the Rd value, the better the material insulates.
It is common for manufacturers to state the Rd value. To calculate this value, you need the lambda value. The lambda value indicates the thermal conductivity of the material and is essential for determining the insulation value.
By understanding the Rd value and lambda value, you can make an informed choice when selecting insulation materials. It is an important part of creating a well-insulated environment that helps save energy and increase comfort.
