Most modern houses are built with two walls and a cavity between them. This cavity is designed with insulation in mind but is often left empty to keep costs down. While the layer of air within the wall does aid insulation you can increase it’s effectiveness by adding insulating material. If your home was built in the last 10 years it is likely that the cavity is already insulated but it’s always worth checking since this could save you over £100 on your bills per year.
Cavity wall insulation requires: