How does solid wall insulation work?
Heat will always flow from a warm area to a cold one. In winter, the colder it is outside, the faster heat from your home will escape into the surrounding air.
Solid wall insulation slows down the rate at which it escapes, keeping as much of it as possible inside your home for as long as possible. How? Insulation works by coating or filling walls with a layer of material that only allows heat to pass through it very slowly. This reduces what is known as the U value of the walls – the rate at which heat can flow through them. The lower the U value, the more slowly heat is lost – and the more money you will save on your fuel bill to keep your home warm.
Solid wall insulation also helps prevent “cold bridging”. Cold bridging occurs when a material that is a good conductor of heat makes a “bridge” between the warm interior and the cold exterior. They are a significant source of heat loss and can lead to condensation and mould forming in buildings. An example of a cold bridge would be the party wall separating two semi-detached homes and spanning the length of the building. Warmth from both homes is conducted along the length of this wall and escapes into the air.