Most people are comfortable with an AC setting between 65-78ºF in the summer. The U.S. Department of Energy (DOE) recommends setting your thermostat to as high a number as possible while being comfortable. This is typically  78ºF during the day and 68-70ºF at night. These recommendations are based on energy studies and optimal comfort. 

Every summer, a battle is waged over the internal air temperature of the home between those who want to cool off and those who want it a little warmer to save money. Unless you live with someone who enjoys the same temperature as you, you know the drill.

The thermostat is “magically” increased or decreased depending on the preferences of those near the thermostat. Debates rage over the optimum temperature, which leads many to ask what is the optimum temperature for your home’s AC and, if two folks are butting heads over the thermostat, is there a happy medium?

What the US Government Recommends

The US Department of Energy recommends the following:

  • Set the thermostat at a temperature that is comfortable and lowers humidity
  • Keep your home warmer when you are away
  • To save money, aim for 78 degrees in the daytime
  • 68 – 70 degrees at night
  • Utilize fans to distribute cooler air efficiently

In addition, the Department of Energy recommends you use a programmable thermostat to get the optimum management control from your unit.

Practical Considerations

Most adults are comfortable in temperatures between 65 and 78 degrees. Once you go below 65 degrees, without taking action to warm up, you run a risk of hypothermia. The young and very old tend to be more sensitive to temperature, so you want to adjust it to help them remain comfortable.

If you keep your thermostat set at 78 degrees, according to the Department of Energy, you will see savings of about 3 to 5 percent for that period. What can throw that number off is if you live in an extremely hot area. The larger the difference between the external temperature and the temperature you want your home to be, the more you will spend on energy bills.

Humidity Matters

A major impediment to a higher ideal AC setting is humidity. Most people find warmer temperatures tolerable if the humidity is low. At the same time, most people become uncomfortable at a far lower temperature if the humidity is off the charts.

The humidity level directly affects what the average person will want their home’s AC set on. Being cooped up in a house with high humidity during the day can be miserable for some people. At the same time, many cannot sleep or do not sleep well with more than 60 percent humidity.

Since your AC is a giant dehumidifier, if you have a lower threshold for humidity, you will probably want your AC set at a lower temperature, so it runs more. If you are ok with higher humidity, you probably are fine with having the thermostat set a little higher.

Personal Preference

Not surprisingly, there is no optimum temperature to run your AC that is universal. Where you live matters, as does what you are used to temperature-wise makes a difference. Some people just like it cooler, and some are fine with warmer temperatures.

If, for example, you are heat sensitive and find anything over 75ºF uncomfortable, your AC needs will vary from someone that does not break a sweat in 90ºF weather.

Here in Nevada, it gets blisteringly hot in the late spring, summer, and most of the fall, so you will likely be used to a warmer AC setting. Likewise, if you live in a cold area, you probably want the AC cooler than someone from a hot region of the country but run your AC less.

All those assumptions are off the table if you are a person who likes cooler or warmer temperatures.

Final Thoughts

While everyone wants an easily packed and unpacked answer, the question of “what temperature should my AC be set to in summer” does not have that type of answer. The outside temperature and humidity levels affect how warm or cool people feel, which affects what they find tolerable. Setting your thermostat to 78 degrees will save money in most places.

Ultimately, however, what you set your AC thermostat at needs to be what makes you feel comfortable and using a smart programmable thermostat can help. If you need help saving energy by installing a smart thermostat in your Las Vegas and surrounding area home, contact our team at Sierra Air Conditioning & Heating today. 

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