is wall insulation worth it
1 It is estimated that the cost to install cavity wall insulation is around Â£150 â Â£500, depending on the number of external walls your home has.2  This figure is for those without access to grants, and will affect whether or not you think cavity wall insulation is worth it. It is also important that your external walls are in good condition. 2  If you home is fairly new, you may find that it already has wall cavity insulation, but your installer will be able to tell you for sure. 3  If your walls have damp issues your home may not be suitable until this problem has been dealt with.