In Virginia I had a programable thermostat. I set it at 57º at night, and 64º when I was home. It was a free standing cottage that started it's life out as carriage house in the 1800's. It was cute and cheap, but drafty and not well insulated. Despite the drafts, turing the heat to 57º at night was effectively turning the heating off. I was cold a lot of the time and showering became an unhappy chore, but it never did me any harm.
Now I live in Seattle, in one of those ridiculously huge condo/apartment things. Haven't turned the heater on yet! It's consistently between 62º and 65º just from passive heating. And strangely the 64º in Seattle 'feels' warmer than the same temp in VA. I'm not sure if it's the extra moisture in the air, or just better insulation. Either way, I'm enjoying the experiment.