My question is as follows: If you wsh to save fuel on a cold day. and you're going to leave your house for a half hour or so, should you turn the thermostat down a few degrees, down all the way, or leave it at room temperature. I said that I would leave it at the same temperature since I'm only leaving for a half hour or so, so by the time I come back the temperature would not have changed much. I should not lower it or higher it because it would be less fuel-efficient and take more energy from the heater to reach the new temperature level. Any suggestions? Thanks much, Sharon.