At a glance
Material construction and its place in the assembly matter. A reflective surface needs an air space; silver colour alone does not define performance.
Radiation, not just light
Insulation concerns thermal radiation. A reflective surface reduces this form of heat transfer; conduction through the rest of the structure still occurs.
Why an air gap?
The reflective surface needs an adjacent air space. Roll thickness alone therefore does not describe the space needed by the finished assembly.
What is inside Thermo+?
Two outer reinforced-aluminium layers and three inner bubble-film layers. Metallised film has a different construction; silver colour is not enough for comparison.