A 2007 study found that homes with programmable thermostats saved an average of 6.5 percent of their energy costs. Using the middle ground of $2300 per year, that's $149.50. That pays for the thermostat the first year and goes into your pocket after that.
The other factor at play is the human one. The more determined you are to save energy, the more you will save.
Do programmable thermostats save money?
According to Energy Star (https://www.energystar.gov/), a federal program to help consumers save energy, 45% of total power use in a home goes to heating and cooling, and the average cost for that comfort is $2100 to $2500 per year. The greater the difference between the outside and inside temperature of your home, the higher the energy costs. Someone willing to be a little cold in the winter in Chicago will save more than someone who has to burn less energy to stay warm.
How willing are you to be a little cold in the winter or hot in the summer?
Can you keep your finger off the thermostat?
Let's look at the numbers. Programmable thermostats typically cost three times as much as manual ones. Let's say we are going to spend $150 on a programmable thermostat, hoping to get that money back with a lower energy bill.
But can you save that 6.5 percent?
If you let your home get uncomfortably hot or cold when you are away and then burn energy getting comfortable when you get home, you won't save much. Experts say you must be willing tosave energy when you are home as well as away. Giving up one degree of climate comfort generally translates into one percent of energy savings.