What is lambda and what is its role in energy costs of buildings?

Lambda (λ) is thermal conductivity determining the value of insulating materials. The lower this coefficient, the better heat-insulating parameters of the material. The lambda coefficient value of the construction material greatly influences the future costs of building heating. Typically used insulation has the λ coefficient at the level of 0.036-0.045 W/mK. Reaching lower conductivity is a great challenge. Purios close cell foams are singled out by low thermal conductivity (λ= 0.020 – 0.022 W/mK) which is still improved.