See full article by Pro Clima International.
The airproofing layer protects the insulation from moisture and condensation from the inside, ensures that the insulation works effectively and provides a healthy indoor living environment.
The thermal insulation separates the indoor from the outdoor climate. The temperature difference between the two climates attempts to become equalised through the flow of air. This means in winter the warm air from the building transfers through the structural elements to the outside. The airproofing layer prevents this air flow, the so-called convection, and therefore the loss of hot air to the outside.
Posted by: Kate Putnam