Reply #29: I think

[quakerboy]

again, basing it off of the good old fuzzily remembered HS experimentation and what I know of physics, via all too many chemistry classes and not a single actual physics class, that you would get a similar energy usage if its 20 out and you set it to 55, and if its 40 out and you set it to 65. Things try to reach equilibrium, a uniform condition throughout, and generally the further that they are from that, the harder they try to get to it(pardon my anthropomorphizing the forces of physics, please).

In my mind your houses are leaky water balloons. Heat is the water. If you fill it up(high heat), it sprays out all the holes rapidly to achieve pressure equilibrium. But if you don't fill it much(lower heat), it just kinda drizzles out. If you just barely fill it(lower heat), and put it underwater(higher outdoor temp), it doesn't even drizzle out so much.