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Thermostats provide an excellent way to control the temperature in the home. The settings used can adjust the comfort level and even reduce the costs of cooling. For example, the optimal setting is 78°F, but the thermostat should only be set to this level when people are home and cooling is needed. According to the U.S. Department of Energy, setting back the system 7° to 10°F for eight hours each day can potentially save up to 10 percent annually on cooling and heating; the milder the climate, the greater the percentage of savings with this strategy.

The 78°F setting is only needed when people are at home. It can be at a higher temperature when nobody is home and a significant level of cooling is not necessary. Setting it warmer can contribute to savings. Generally, the less variability between the indoor temperature and how hot it is outside, the lower a monthly cooling bill may be.

For the best possible savings, set the inside temperature as high as possible while still keeping it comfortable. In doing so, it’s also possible to control humidity levels at home as well.

Using a Thermostat with an Air Conditioner

People often try to cool their homes faster by choosing a colder setting and turning up the air conditioner, but this is not an effective strategy. The excessive use of the system can lead to higher expenses. Plus, it won’t cool things down any faster than a normal setting would.

Another benefit to higher interior temperatures in summer is a slower intrusion of heat. Energy can, therefore, be saved by raising the thermostat setting. Even in the wintertime, less variability between inside and outside can slow heat loss and the loss of energy. The same basic concept applies in both cases. Also, for cooling (and heating too), every extra degree the system is set to amounts to a 6 to 8 percent increase in energy consumption.

Fans are a good way to boost cooling. The flow of air creates an effect that helps people cool off. Known as the wind chill effect, this means that using an air conditioner and fan together will allow for as much as a 4°F increase in the thermostat with no impact on comfort.

Setting a Thermostat for Comfort

It can’t hurt to try a higher setting in the summer. However, not everyone is comfortable with an interior temperature of close to 80°F and people with health issues might need a lower setting. Raising it to 85°F at night may not be suitable for everyone either, but energy efficiency and comfort are a delicate balance.

Large jumps in temperature settings can waste energy. Therefore, thermostats should be adjusted in one-degree increments. Leaving the setting for a few days can provide an opportunity to see if the comfort level is optimal. After a few days or a week, lowering the setting another degree will help get closer to the ideal temperature and maintain the most energy efficiency possible.

Although this strategy may take some time and patience, it can lead to higher efficiency and savings in the long run. Also, wearing light and loose clothing is typically more comfortable in the summer and can help contribute to feeling cooler. Lower settings on the thermostat may not be necessary at all.

On the other hand, being impatient can be costly. There’s no merit to turning the setting down as low as possible to make a room cooler. It does not speed up the process.

How to Get the Most Out of Programmability

Programmable thermostats provide the opportunity to put all the appropriate settings in, so manual adjustments aren’t needed from day to day or at any specific time. They can be set to accommodate the schedule of anyone in the house. Pre-programmed settings are often included, but are based on a model that considers savings and comfort; they might not be ideal for everyone.

According to ENERGY STAR, the best setpoint temperature to cool a home at wake time (approximately 6:00 a.m.) is greater than or equal to 78°F. During the daytime hours, an increase of 7°F is optimal for savings. The thermostat should be set back in the evening, and up about 4°F after 10:00 p.m. Programming the system allows for the temperature to be adjusted automatically based on the usual sleep and wake times of everyone in the household. Higher settings are recommended for when nobody is home for an extended period of time. Consider higher set-points for energy savings when the home is unoccupied for at least eight hours, but making such adjustments when people aren’t around for four hours can save energy and costs as well.

With a programmable thermostat, one can also:

  • Override the setting if a temporary decrease or increase in temperature is required; consistently doing this will raise energy bills, but over short periods, it can avoid sacrificing comfort.

  • Use the “hold” or “vacation” feature to set the interior temperature higher if the home will be unoccupied for a weekend or longer. Managing day to day settings this way is inefficient.

  • Install a thermostat for each section of the house, if it has multiple cooling or heating zones. Programmable setbacks make things convenient and contribute energy savings.

Optimal Settings and Thermostat Location

Regardless of what the temperature is set to, the location of the unit can affect how it works. Thermostats should be placed where there is not direct sunlight or a draft. Proximity to a window, door, or skylight can decrease accuracy. The natural air currents that flow through a room should reach the unit so its readings are the most accurate; even furniture can block the natural flow of air, so the device should be somewhere in the open.

The recommended settings for comfort and savings serve as general guidelines. Many people are more comfortable at temperatures other than the optimal ones, but it’s possible to achieve the most energy efficient setting that contributes to the greatest comfort all summer long.