The Department of Energy estimates homeowners using programmable thermostats this way can save as much as 15% a year on heating and cooling by simply setting back the temperature by 7°-10°F for 8 hours a day from its normal setting.
But as it turns out, the only real pro to keeping your thermostat one temperature is convenience. Sure, when you're away on vacation or gone for the weekend, the consistent temperature is efficient, but when you're at home, there's really no additional benefits.
Even though your cooling unit will have to run for a while to get to the temperature you prefer, it still saves more energy — and money — than running it constantly. If you have a programmable thermostat, even better.
Set your thermostat to 68 degrees Fahrenheit in the winter
According to ENERGY STAR, setting your thermostat to 68 degrees Fahrenheit (20 degrees Celsius) when you're home is the ideal balance of comfort and energy efficiency.
The startup process for a furnace consumes more energy than simply running the entire time at one set temperature, costing you additional money. To maximize efficiency, it's best to keep your furnace (or AC) at the same consistent temperature for long periods of time.
For every degree that you lower the thermostat can help you save up to 1% on your heating costs. So, if you turn down the heating eight degrees for about eight hours a night, you can enjoy a saving of approximately $180 annually on your heating.
According to experts at the Energy Saving Trust, the idea it's cheaper to leave the heating on low all day is a myth. They're clear that having the heating on only when you need it is, in the long run, the best way to save energy, and therefore money.
The Department of Energy estimates savings of about 1 percent for each degree of thermostat adjustment per 8 hours, and recommends turning thermostats back 7 to 10 degrees from their normal settings for 8 hours per day to achieve annual savings of up to 10%.
Temperature When You're Away
When you're not home, you should set your thermostat between 60 and 65 degrees. Things to consider are plants, animals, house safety, and outside weather conditions.
A safe temperature is accepted to be between 68 and 74 degrees Fahrenheit for people above the age of 65. The temperature inside your home should not reach below 68 degrees Fahrenheit in any case, as that increases the risk of respiratory disease and even hypothermia if there is prolonged exposure.
Downsides of a fluctuating temperature
Constant jumps in the temperature setting can have a similar effect if they occur often enough. All of this means that your AC unit is working too hard and will wear down more quickly, leading to costly repairs and early replacement.
Your AC will actually run longer overall if it is left on all day instead of being shut off. If you turn it off for part of the day, it runs less and results in more energy savings for you. In almost all cases, it will save you money to shut off your AC while you are away from home.
The ideal temperature to keep your thermostat set at over the summer is 78 degrees. This slightly elevated setting will help balance your AC costs out, so you are not wasting money on cool air when your thermostat is already low.
Heating a home tends to cost more than twice as much as cooling a home.
Not so fast. The U.S. Department of Energy says an indoor temperature of 65 degrees Fahrenheit at night is best. Setting your thermostat to a lower temperature at night may actually help you sleep better. Medical experts know that our body temperature drops at night.
According to the Department of Energy, 68 degrees Fahrenheit is the sweet spot when you're home during the winter. You can also drop it down a few degrees when you're sleeping to save more energy, as you'll be under the blankets for extra warmth.
Heat constantly escapes your home when it's cold outdoors, which is why it makes sense to lower the thermostat when you're not there. But turning off the furnace in the winter—especially when you're away for long periods of time—runs the risk of frozen pipes that could easily burst when they thaw.
To some people, 70°F (21°C) is the ideal temperature. To others, anything below 65°F (18°C) is cold. But if you follow EPA guidelines, 68°F is good enough for any person. The lowest acceptable temperature for a house is 65°F (18°C).
The lower the temperature is inside of the home, the slower the rate of thermal energy loss. To achieve optimal comfort, it is recommended for homeowners to set their thermostats between 68 to 72 degrees while there are people inside of the home.
We're grateful to the DOE, EPA, and other government and industry organizations for making some valuable predictive models for heating and cooling. For example, the DOE's Energy Savers website says that you can generally save 3% on your heating bill for each degree that you turn your thermostat down during the winter.
A broken or faulty thermostat can force your system to constantly turn on and off. This makes the system function inefficiently and will cause your electric bill to rise.
This is more of a personal question, as different people feel comfortable at different temperatures. Since 72 degrees is generally agreed upon to be an ideal indoor temperature, most people would probably still feel comfortable setting their AC units slightly higher than this, perhaps at around 75.