Setting Your A/C Temperature When Nobody Is Home

On hot summer days, your air conditioning can feel like a lifesaver. But what is your AC doing when you’re not at home? You don’t want to waste electricity cooling a bunch of empty rooms, but you also don’t want to come home to a miserably warm house after a long day. Striking the right balance can be difficult. The best temperature setting varies from person to person, home to home, and AC unit to AC unit, but with a few of these handy tips you should be able to determine the best temperature setting for when you’re away.

Saving Money

Obviously, it’s easy and comfortable to keep your AC running constantly at the lowest temperature you want, but if you choose to do this then you’re forcing your unit to work hard for no reason. When nobody is home to enjoy the cool air, there’s no reason to keep your air conditioner running at full blast, and doing so only wastes money. The air conditioner is one of the biggest consumers of electricity in your home, and turning the thermostat up to a slightly higher temperature is one way to save on your utility bills each month.

Going Green

Also, reducing your electricity consumption is a good way to help protect the environment. Energy inefficiency means that more electricity must be produced, which in most cases means more coal must be burned. This contributes to air pollution, climate change, and environmental impacts in and around coal mines. Raising the thermostat a few degrees higher is a great step to take when going green.

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Keeping Cool

Using your air conditioner more efficiently doesn’t mean that you have to sweat through the summer. You can easily turn up the temperature or turn off your air conditioner entirely when you aren’t at home, and turn it back down when you are. If you have a multi-split air conditioning system (where the temperature of each room can be controlled separately), then you can also keep specific rooms warmer when you aren’t using them. Turning the thermostat up a few degrees when you’re asleep is another good way to reduce your energy usage, and you can turn it up several degrees if you’re going to be gone for an extended period of time. Each degree you raise on your thermostat will save you anywhere from 2%-5% on your electric bill.

AC Myths

A common misconception is that changing your temperature settings this often can hurt your air conditioning system, because you’re forcing the air conditioner to “work harder” to cool your home after letting everything warm up during the day. This is not true. Your air conditioner is actually more efficient when running for a short time on full blast than it is running constantly on a low setting. This is because your home gains heat from the surrounding environment more slowly when it’s warm inside. Turning your AC off and on repeatedly is a much more effective use of electricity.

Maximum Efficiency

In addition, periodic use becomes more efficient the longer you leave the air conditioner off. Imagine its 90 degrees outside, and if you leave your air conditioner off for an hour, your home’s temperature will also climb to 90 degrees. If you leave your air conditioner off for two hours, your home’s temperature will be 90 degrees, and if you leave it alone for three hours, the temperature will still be 90 degrees. No matter how long you leave the air conditioner off for, it will take the same amount of energy to return your home from 90 degrees to the temperature you prefer. But if you leave your air conditioner running for two hours, it will consume twice as much energy as it does in one hour, and if you leave it running for three hours, it will consume three times as much. The longer you leave it running, the more energy it will consume. Turning off your air conditioner and turning it back on again saves you much more electricity than running it does.

Programmable Thermostats

Many people have concerns about comfort when they turn down the thermostat; nobody likes sweating through the heat while they wait for their house to cool down again. One easy solution is to use a programmable thermostat, such as the Nest, which allows you to heat and cool your home at a designated time. These devices can store a number of daily settings which are activated on a pre-set schedule, allowing your air conditioner to turn on and off automatically. This means that you can set your unit to start thirty minutes to an hour before you get home, so that by the time you arrive your house will be nice and cool. You’ll never be able to tell that your air conditioner was turned down (or off) while you were away.

Programmable thermostats allow you to set consistent schedules, so that you don’t have to worry about forgetting to turn the AC off. Although some AC systems will not work with programmable thermostats, most will; if you have a window air conditioner you might be able to find a model that integrates this setting with the controls. Smart thermostats–such as Nest–will build a personalized cooling schedule for your home. After tracking your temperature preferences for a week, Nest will automatically start setting on its own, saving you energy and money.

Finding the Balance

So how exactly do you determine the best temperature for your home? There is no one-size-fits-all solution, but most homeowners can set the thermostats as high as 88 degrees Fahrenheit when nobody is at home without sacrificing comfort. You may need to adjust this depending on a variety of factors, including:

• The climate in your area
• Whether you have a pet that needs to stay cool
• The size and effectiveness of your AC unit
• The times of day you’re home

The biggest question is whether you are comfortable or not. If you’re feeling too warm, don’t be afraid to turn your thermostat down a degree or two. If your house is too hot when you get home, have your air conditioner turn on a few minutes earlier. And if you’re feeling just fine, try adjusting your thermostat just a little higher or turn your unit off for a little longer and see if you notice the difference. After a little bit of trial and error, you’ll be surprised at how cool your house can stay without running the AC all the time.

Finding the right temperature setting can be difficult, but it’s worth it. Reducing your air conditioner use when nobody is home is a great way to save energy, benefiting you as well as the planet.