I put in a digital programmable thermostat, too.
The old one was original with the house, which is 30 years old. It was getting bad last winter, and by this summer you had to turn the dial at least seven or eight degrees below the present temperature to even get the AC to come on.
This one, by comparison, is a delight. So nice and accurate!
I'm also going to invest in one or two small space heaters and some firewood. We plan to wear sweaters, use blankets, keep one or two rooms at about 65, and just let the rest of the house be chilly. Screw the natural gas companies.