One of the most prevalent (and maddening) myths about home heating is that turning the thermostat down at night and when you’re not home doesn’t save energy. Let me be clear – this is false.
The idea behind the myth is that once a house is warmed to the temperature choice (say 68 degrees F) it takes less energy to keep it at that temperature than it would to turn down your thermostat (in the winter) and let it cool by 10 or fifteen degrees when you go out, then reheat it when you come home later. Likewise at night when you go to bed. The idea is kind of like fuel conservation in your car. When you are stopping and going around town your fuel efficiency is much worse than when you are cruising on the highway.
But your house is not a car (thankfully).
The simple truth is that the amount of energy you use to heat your home is directly proportional to the difference between the indoor and outdoor temperature. We all know this intuitively – in a cold winter it costs more to heat your home to the same temperature than it does in a mild winter. So, if you let the temperature in your house drop (many suggest to 55 degrees F) while you are out of the house and sleeping in your cozy bed at night you will absolutely use less energy. While it does take a little ‘extra’ energy to raise the temperature back up, this is less than the energy you save. The actual savings you’ll see depend on a variety of factors, but a good rule of thumb is that you can save about 2% for every degree you lower the thermostat in the winter.
And a final word of advice – when you turn your thermostat back up don’t set it higher than the temperature you want, it won’t make your house warm up any faster and you will most likely forget to adjust it later, turning the exercise into a money-waster rather than a money-saver.
Here at GreenHomes America we usually advise customers to set back their thermostats by 10 degrees F when they are not home, or are asleep (unless you have extenuating circumstances such as an infant, ill, or elderly family members, in which case you should defer to your doctor’s advice). For the best reliability, and a toasty warm house upon waking or arriving home, a programmable thermostat can be used… more on them next time.