What is external wall insulation?

External wall insulation (EWI) refers to the technique of fitting insulation to the exterior surfaces of a building's walls. This is typically done using materials such as expanded polystyrene, mineral wool, or phenolic foam, which are then covered with a special type of render or cladding to protect the insulation from weather conditions and improve the building's aesthetics. The primary benefits of EWI include significant reductions in energy consumption by keeping heat in during the winter and out during the summer, leading to lower heating and cooling bills. Additionally, EWI can help prevent damp issues within the walls, extend the life of the exterior walls by protecting them from the elements, and potentially increase the property's value. This method is particularly beneficial for older buildings that lack cavity walls, providing a retrofit solution that enhances comfort and efficiency without reducing interior space.