Cavity wall insulation is regarded by many as one of the most effective ways in which homeowners can save energy.

Millions of homes in Britain have already had cavity insulation installed, while many more are becoming aware of the benefits every day.

Developed in the early 1930’s, cavity walls feature on the vast majority of houses built ever since. Cavity walls consist of an inner and outer wall, with a gap of more than two inches between them. Their original development was an attempt to prevent rain penetrating properties in exposed coastal regions.

Modern consciousness of energy efficiency raised cause for concern over cavity walls, as they allow considerable heat energy to pass through and out into the atmosphere.

The escaping heat impacts not only on the environment but also on domestic heating bills – as homeowners turn the heating higher to compensate.

Insulating the gap between cavity walls helps to reduce the energy you lose, cutting carbon dioxide emissions. It’s a quick and surprisingly easy process for an installer to carry out.

How is it done?

The most common forms of cavity insulation include polystyrene beads, foam, or mineral wool. Each has its own unique properties, yet all share the aim of keeping heat in and moisture out.

Installers can advise on the most suitable material for your home, and then simply inject it into the wall cavity from the outside. The process rarely takes more than three hours and costs around £500 – though naturally this depends on the size of the property.

Cavity insulation is best left to the experts. A poor job can leave unfilled pockets of air which attract condensation to inside walls.

Payback period

According to the Energy Savings Trust, cavity insulation could save you around £90 on your annual fuel bills. With an estimated installation cost of £500, your cavity insulation may well have paid for itself after five or six years.

You’ll also make CO2 savings of around 750kg every year.

Such is the environmental importance of cavity insulation, the government offers grants to help people install it at lower cost. To find out if you’re eligible for a government grant, visit the EST website.