Examine the thermostat's battery. Your thermostat's batteries may need to be adjusted. When the thermostat in your home is driven by batteries, make sure you replace them at least annually or as necessary. While Furnace Repair Services some thermostats use batteries, Other people are linked into the house's electrical process. How is yours energized? Whenever a battery must get replaced, some units that use batteries will often display a lower-battery indicator.