The main difference between a digital programmable thermostat and an analog thermostat is the level of functionality. In addition, the increased accuracy of a digital thermostat helps lower the cost of cooling and heating by some estimates as much
as 30 percent.
With a digital thermostat, basic models may allow you to simply set a temperature, such as 76 degrees, and when the air is cooled down to this temperature the unit shuts off. An analog unit basically does the same thing. However, without the digital component, the unit may actually be cooling down to 74 degrees before it stops cooling.
More advanced digital thermostats may have timers to automatically turn the unit off between the hours of 9:00am and 4:00pm and then set to cool down to a temperature of 76 between 4:00pm and 8:00am the next day. Analog thermostats are not able to be programmed by time of day and must either be set to “Auto” and dialed on to a temperature that is comfortable or must be turned off and on manually.
Any central AC system can be upgraded to a digital thermostat. Over time this can save you a lot of money on your electric bill because it will allow your system to be more efficient and last longer..