The official projected saving taken from an ad I heard on the radio is 2%. I mean wow! I understand that they still don't work across all companies and if you switch suppliers, you may need another meter fitted. As I have said before if you have a family of teenagers and want to keep an eye on what is being used or left on than I can see the point in having one, for me on my own, if something is switched on its because I want it switched on. I send in readings online whenever I am asked and cannot remember the last time I had an estimated bill. If I am made to have one, or if I move and there is one in the new house then fine but otherwise getting one fitted seems to me to be just a hassle and no benefit.