External cladding insulation your external walls is one of the best ways to save energy at home. It reduces heat loss, improves thermal comfort, and makes your home more environmentally sustainable – as well as saving you money on your heating bills.

But how does external insulation work? And which type is right for you?

A quick summary: EWI is an exterior cladding and insulation procedure that involves applying an insulative layer to the face of the wall, covering it with a weatherproof render or cladding, then covering all with a protective finish. The systems available vary, with expanded polystyrene (XPS), mineral wool and phenolic foam among the most common materials. They’re used in solid brick, concrete and timber frame houses. They’re not suitable for homes with partial fill cavity walls or those fitted with solid block wall insulation, which was compulsory in new builds from the 1990s.

Beyond Aesthetics: The Crucial Role of External Cladding Insulation in Energy Efficiency

It’s a better option than lining internal walls and, unlike cavity wall insulation, it can be used in existing buildings, including Listed and Heritage properties. It’s also less disruptive and more cost-effective than re-plastering.

The main disadvantage of EWI is that it can change the appearance of a building, so it’s not ideal if you’re attached to your original brick or stone façade. It can also cause problems around soffits and drainpipes and can affect the appearance of a window or door frame. It may also need to be repaired from time to time, as the finish can deteriorate over time.