In general, every ENERGY STAR qualified programmable thermostat comes with four pre-programmed settings and maintains those settings within two degrees. Many qualified models also come with additional features, such as:
Digital, backlit displays
Touch pad screen programming
Voice and/or phone programming
Hold/Vacation features
Indicators which tell you when its time to change air filters
Indicators that signal malfunctioning of heating/cooling systems
Adaptive Recovery/ Smart Recovery features control features that senses the amount of time it will take to reach the next set-point temperature, and reach desired temperatures by the set time