An electronic combined programmer and thermostat allows you to control the heat source from sending heat to the system. This device allows you to program multiple time periods and different temperatures to your needs. It can also be set to work as a simple on/off switch for your system. The new 3rd generation Google Nest learning thermostat is one of the latest innovations that "learns" based on past history, what temperature you like you home to be and sets it at the temperature automatically. Easy to use and set from you mobile phone.