A wall thermostat switches the heating on and off depending on the temperature in the room at that time. If the air temperature goes above the temperature you have set on the thermostat, then it switches the heating off. It turns it on when the temperature falls below what you have set.
One way to save a significant amount on your heating bill is to turn your thermostat down by 1 degree. You will probably not notice the difference in temperature, and it can save up to 10% off your heating bill. However, this is a trick you can only play once, and too low a temperature inside your house can be bad for your health.
Old analogue wall thermostats are set by turning a dial to the desired temperature. They are relatively imprecise and can cause the temperature in the room to fluctuate between 1 degree above the temperature that you want and 1 degree below it. It can be worth replacing your old thermostat with a new digital thermostat, which also has a programmable timer included. This means that you can control both the temperature and the time that your heating is on from one device.
