Colin, CC, I wonder how they can 'guarantee' what you will save, as each of us consumes gas/electricity in our individual way? Granted, you will save something if you have insulation added, for example, but - for myself - I would worry that it was going to be enough to repay that loan asap. Presumably, too, you would not 'save' anything on heating costs over the summer, so does interest accrue then? Is it also means tested??