Internal and External Wall Insulation
As with cavity wall insulation, this is a very good way of saving money through reducing your heating bills. Unfortunately, the cost and difficulty of implementing this make the return on investment much longer.
The average saving in a typical house is about £400 per annum. With installation costing approximately £7,000 for internal and £12,000 for external walls, the return on this investment is much longer then other energy saving ideas.