It is a common misconception that you use less energy by keeping your heat at one temperature than by lowering and raising the temperature according to when you are home. The US Department of Energy suggests that “you can save as much as 10% a year on heating and cooling by simply turning your thermostat back 7°-10°F for 8 hours a day from its normal setting.” The practice that saves the most on heating bills is lowering the temperature when you are not home or are asleep. There is a similar misconception about air conditioning; it actually saves more electricity by turning the AC off when you leave home and on again when you return. How can you remember to turn the thermostat up and down several times a day? An easy solution is to install a programmable thermostat. A programmable thermostat allows you to pre-set heating and cooling temperatures according to your schedule. You can also set the heat to turn on an hour before you get up and an hour before you return home and then lower the temperature when you leave for work and are asleep. When you go on vacation, your programmable thermostat can be set to “hold” at one temperature so that you are not unnecessarily warming or cooling the house while you are away.
The US Department of Energy offers this bit of additional advice:
“Avoid setting your thermostat at a colder setting than normal when you turn on your air conditioner. It will not cool your home any faster and could result in excessive cooling and, therefore, unnecessary expense. A common misconception associated with thermostats is that a furnace works harder than normal to warm the space back to a comfortable temperature after the thermostat has been set back, resulting in little or no savings. In fact, as soon as your house drops below its normal temperature, it will lose energy to the surrounding environment more slowly.”*
*https://www.energy.gov/energysaver/programmable-thermostats; Retrieved 9/10/23