If you have no insulation In your cavity walls or if your insulation is old and ineffective, you will save hundreds of pounds every year on your heating bills and it will keep you warmer.
Cavity wall insulation is installed from the outside of the property. Thermal beads are used so there is no danger of water buildup or damp forming on your walls.
If you have a look at the video it explains it very clearly which should give you peace of mind.
To find out if you are eligible for free Cavity Wall insulation click HERE
For more information please refer to Which? and the National Insulation Association (links below).