Humane Interface by J. Raskin had some interesting points about how to make low tech interfaces.
You need essentially eliminate "modes" - like the clock/set time/radio mode buttons on your alarm clock. I'm not saying he's right - but he's worth reading.
The temperature of the house is not uniform - areas are colder than others. But when you heat up to 68F - then the really cold areas of the house stay (usually) above freezing. If you let the house drop to 60-55 F - there's no guarantee that the colder parts of your walls and pipes freeze.
Moist air from cooking increases the humidity in the house. The walls of the house are cold, the moisture condenses on the cold walls keeping them damp for the entire winter.