A broken or faulty thermostat can force your system to constantly turn on and off. This makes the system function inefficiently and will cause your electric bill to rise.

Is it cheaper to leave your thermostat at one temperature?

Says the U.S. Department of Energy on energy.gov, "You can easily save energy in the winter by setting the thermostat to 68 degrees while you're awake and setting it lower while you're asleep or away from home." Figure you save up to 1 percent per year on your heating bill for each degree you set back the thermostat ...

Does turning down the thermostat save money?

The good news is that yes, turning down the thermostat to save money does lower your overall heating bill. ... The U.S. Department of Energy estimates you'll save between five and 15 percent on your electricity bill if you lower your thermostat by 10 to 15 degrees for an eight-hour period.