Since installing loft insulation, I have noticed a subtle change, but one that is most definitely there. Every bill that we receive now is a little bit smaller, and because of the fact that we got this insulation done completely for free, it is a great thing. I think it is due to the fact that, although we do still put the heating on in the evening, the new insulation makes it so that it doesn't need to be on as high, or for as long. So we are definitely getting some benefit from it! It would be great to see how some other people feel about it, too.