Put your thermals away.
Although it isn't a primary insulation material, solid Interior uPVC Direct Cladding does have insulating properties, as a contributor to thermal efficiency.
Low Thermal Conductivity: uPVC (unplasticized polyvinyl chloride) is a type of plastic that is a poor conductor of heat, which is why it is used for window frames reducing heat transfer out of your home.
Cladding your walls, stops a a high percentage of heat going out through the walls, helping to keep you warm during the winter and cooler in the summer.
A "Dry Wall" has significant benefits because it creates a moisture barrier. Fully waterproof Direct Cladding protects underlying walls from moisture and condensation, preventing damp. This much higher thermal performance than wet walls helps to maintain the wall's existing insulation.

