How old is your thermostat? I see really old ones all the time. They don't work well and are inaccurate. Maybe it's time to change them. You can do it yourself and save some money. Most models come with instructions and are simple to install. Just connect the red wire where it says red, white to white and so on. It couldn't be any easier. You'll see results (lower energy consumption) immediately.
Also remember that most older dial type thermometers have mercury in them. Please dispose of them properly. Many communities have recycling programs that will allow you to drop of these devices. And while we're talking about proper disposal of hazardous materials did you know that most smoke detectors have a small amount of radio active material in them that requires proper recycling or disposal.