Your thermostat is like the eyes and ears of your HVAC system. It will tell the system when it needs to turn on and when it needs to turn off, so the proper functioning of your thermostat is essential to a properly working HVAC system. Take, for example, a thermostat that is of an older model and has issues reading the correct temperature. It could lead to your system running when it doesn’t need to, costing you extra.
Another shortcoming of an older thermostat is that you are unable to program it. With modern, digital thermostats, you can set timers for when you want the system to keep the temperature at a level that is comfortable for you, as well as, when the home is going to be empty, not needing the HVAC system to run as hard. You could even go one step further and get a smart thermostat that will learn your habits and that can be controlled just using your voice.