Just before we go to the other witnesses, if they want to speak to this, I just want to pick up on your earlier point about the difficulty of retrofitting and the costs that go along with that. You specifically mentioned that there has to be a payback so that it makes good financial sense because, ultimately, it is shareholders' or business owners' money and equity at stake. I think that's something we always need to keep in perspective, because when we're retrofitting our own buildings we should think like a taxpayer.
I agree with that and I would ask the other witnesses to comment on it.