@Anne van der Bom again...Re: you're hot water calculation.
1. 15 to 35C. The average human is about 38C, A 35C bath, that's not hot it's tepid. The author was using 10C to 50C, that's a lot more typical, though if we want to skew the numbers I suppose we could be warming Saharan water from say a balmy 45C to 50C and save a whole lot of energy. Makes ther case better!
2. 70L. Based on a typical Canadian Bathtubs internal size (maybe Europe's different) of roughly 142cmx61cmx36cm, 70L gets me 8.1 cm of soaking glory. The author suggests larger dimensions and deeper water, again more realistic.
So the hot bath is now defined as 8cm of lukewarm water. I'd like everyone to go home and try this out tonight.
3. Now we heat it. You assume a 90% gas heater. Why? This gets around the irritating 35% generating efficiency you goose the 2W standy unit with. Nice.
Personally, When I bath I use a small bucket (10L) and limit the temperature to a balmy 25C. I like it brisk. Did I mention I have black solar coils on my thatch roof in my equatorial abode, so I'm pretty efficient.
Tongue in cheek aside, you can manipulate your numbers to make your case, and in your case I think perhaps you're being a bit generous to your case. Again, you're not being skeptical, you're agenda is obvious here. From what I've read of the paper, the author is making ballpark calculations, and it's obvious, he makes no effort to hide this. The values he chooses are general, typical, what the average person uses. Be average, it's what everyone else is, and if you base your case on anything else, your argument doesn't hold much water (hot, tepid or brisk), because it assumes the best of people, that they'll change out of the good of their heart. Perhaps you've noticed, that's not reality.
Sollace