So you here lowes and home depot saying save $ 100 dollars a year on a new digital thermostat. So you go into the giant box store into the plumbing and heating section and you see a huge selection of thermostats… Unfortunately you have now idea what a line voltage, low voltage is and which model or make is best and which one will work for you..  Best Programmable Thermostat website will try to help

Line Voltage	Low Voltage	Heat Pump	Electric Heaters	Energy Star
Line Voltage Wall Thermostat	Low Voltage thermostat	Heat Pump Programmable Thermostat	Electric Heater Wall Thermostat	Energy Star Rated Wall Thermostat