Enter your current annual heating/cooling cost and expected setback hours per day to see potential savings.
The U.S. Department of Energy estimates roughly 1% savings per degree of setback held for about 8 hours — this scales that guideline to your actual setback schedule and degree amount.
A programmable or smart thermostat's real value comes from consistently applying a setback schedule you might forget to do manually — letting the house drift a few degrees warmer in summer or cooler in winter while you're away or asleep, then recovering before you're back. This compounds with any changes from a more efficient heating system for a fuller picture of annual HVAC cost.
Generally yes up to a reasonable point, but very large setbacks can require more energy to recover to a comfortable temperature quickly, and comfort trade-offs limit how far most households want to go.
The savings shown here mainly come from the setback schedule itself, which any programmable thermostat can deliver — smart thermostats add convenience features like geofencing and learning algorithms that can capture a bit more savings by adapting automatically.