The only thorny part with the new heat values in Railcraft, is how incredibly hard it would be to heat up a high pressure boiler. I'll wait for someone to make the "electric heater" mod.
I had a small discussion about it on BC github a few days ago.
TL: DR
if the time spent heating up a boiler is significant your energy production is badly designed.
Also, never use HP boilers if efficiency is a concern for you.
Axing heatup fuel costs in 1.7 in favor of scaling steam output by temperature? Really liking that idea, thanks for the link (even though that was not what you wanted to link :P)
(even though that was not what you wanted to link :P)
Actually it was exactly the thing I wanted to link. I wanted people to see the whole discussion, not just what I said there.
Though I guess the confusion might have been that you had electric heaters in mind when talking about "it" while I had just general boiler and energy production mechanics 
