Turning Off Your A/C

Does Turning Off Your A/C When You’re Not Home Actually Save Money?

Summer in Tucson means scorching temperatures and high electric bills. Many people wonder if turning off their air conditioner (A/C) when they’re not home can help reduce those costs.

It’s a common belief that switching the A/C off during the day and turning it back on in the evening will save money. But does this strategy really work? Let’s explore what experts say and find out the most effective ways to keep your home cool while saving money.

Understanding the Cost of Running an A/C

Running an A/C unit can be expensive, especially during the hot summer months. According to a recent study, the average electric costs for June through September are expected to reach $719 this year, up from $476 for the same four-month period a decade ago. This significant increase is due to a variety of factors, including higher energy prices and more frequent heatwaves.

For cash-strapped households, the thought of saving money by turning off the A/C when no one is home is appealing. However, the reality is that this method may not be as effective as it seems.

The Science Behind Cooling Your Home

To understand why turning off your A/C might not save as much money as you think, it’s important to know how A/C units work. When you turn off the A/C, the temperature inside your home rises quickly. Once you turn it back on, the unit has to work extra hard to bring the temperature down to a comfortable level. This process uses a lot of energy.

Andrew Dobbins, owner of Intelligent Design Air Conditioning, Plumbing, Solar, & Electric, explains, “By turning it off, you’re making your A/C go full-throttle every single time it’s turned on, and that gobbles up much more electricity than just maintaining the desired temperature.”

In other words, the energy used to cool down a hot house can be greater than the energy saved by turning off the A/C for a few hours. This is especially true in hot and humid climates like Tucson, where the A/C has to work even harder to remove humidity from the air.

The Temperature Setback Strategy

For most households, a strategy called “temperature setbacks” is the most effective way to cut cooling costs. This involves raising the thermostat setting by a few degrees when you’re not home and lowering it when you return. This method keeps the A/C running at a lower capacity, preventing it from having to work too hard when you come back.

Andrew Dobbins supports this approach. He says, “It’s much better to just set the temperature up a notch or two while you’re away and then tune it down again when you’re back.”

This method is simple but effective. For example, if you normally keep your home at 75 degrees, try setting the thermostat to 80 degrees when you’re away. When you return, lower it back to 75 degrees. This way, your A/C doesn’t have to cool down from a very high temperature, saving energy and money.

Using a Smart Thermostat

One of the best tools to help with temperature setbacks is a smart thermostat. These devices allow you to set a cooling schedule for each day of the week. On workdays, you can program the thermostat to raise the temperature when you leave the house and start cooling down before you return.

According to the U.S. Department of Energy (DOE), using a programmable thermostat to set back the temperature by 7-10 degrees for 8 hours a day can save as much as 10% on heating and cooling costs. The DOE recommends setting your A/C to 78 degrees when you’re home for optimal savings.

Smart thermostats also come with features like remote access, so you can adjust the temperature from your phone if your schedule changes. This flexibility ensures that your home is always comfortable without wasting energy.

The Impact of Home Insulation and Sealing

Another critical factor in keeping your home cool and saving on energy costs is proper insulation and sealing. If your home is not well-insulated, cool air can easily escape, making your A/C work harder.

Sealing gaps around windows and doors can make a big difference. Use weatherstripping or caulk to close any gaps where air might leak. Adding insulation to your attic and walls can also help keep cool air inside during the summer and warm air inside during the winter.

In Tucson, where the sun can be intense, it’s also helpful to use reflective window films or shades. These products can block some of the sun’s heat, keeping your home cooler without putting extra strain on your A/C.

The Role of Regular Maintenance

Keeping your A/C unit in top condition is essential for efficient operation. Regular maintenance can help prevent breakdowns and ensure that your system runs as efficiently as possible.

Here are some maintenance tasks you should perform regularly:

  • Change the Filters: Dirty filters can restrict airflow and make your A/C work harder. Check your filters every month and replace them at least every three months.
  • Clean the Coils: The A/C coils can accumulate dirt and debris, which impedes heat transfer. Clean the coils at least once a year to maintain efficiency.
  • Check the Fins: The fins on the evaporator and condenser coils can bend and block airflow. Use a fin comb to straighten them if needed.
  • Clear the Area Around the Unit: Make sure there are no leaves, grass clippings, or other debris around the outdoor unit. This ensures proper airflow and prevents overheating.

Andrew Dobbins emphasizes, “Dirty coils can impede heat transfer, and dirty filters can slow air flow, causing your A/C to work harder for the same output. In the short term, this can cause higher energy bills. In the long term, it can lead to potential breakdown of your unit.”

Using Ceiling Fans and Other Cooling Methods

Ceiling fans can complement your A/C by circulating air and making you feel cooler. Make sure your ceiling fans are set to run counterclockwise in the summer, which pushes cool air downward.

By using fans, you can raise your thermostat setting by about 4 degrees without sacrificing comfort. Fans use much less electricity than A/C units, so this can lead to significant savings.

Other methods to stay cool include:

  • Close Blinds and Curtains: Keep blinds and curtains closed during the hottest part of the day to block out the sun’s heat.
  • Use Blackout Curtains: Blackout curtains can be particularly effective in keeping your home cool by blocking UV rays.
  • Open Interior Doors: Keep interior doors open to allow for better air circulation throughout your home.

Managing Electricity Use During Peak Hours

Electricity rates are often higher during peak hours, usually from 4 p.m. to 9 p.m. Shifting some of your electricity use to off-peak hours can help lower your energy bill.

For example, run your dishwasher, laundry machines, and other major appliances early in the morning or late at night. If you have an electric vehicle, charge it overnight rather than right when you get home. These small changes can add up to significant savings over time.

Andrew Dobbins advises, “Be aware of time-of-use pricing in your utility area. Utilities can charge three to four times the standard rate for energy used during certain peak hours.”

The Importance of Professional Assistance

Sometimes, the best way to ensure your A/C system is running efficiently is to get professional help. A licensed HVAC technician can perform a thorough inspection and tune-up of your system, identify any issues, and make necessary repairs.

Professional maintenance can also extend the life of your A/C unit, saving you money in the long run by delaying the need for a replacement.


While turning off your A/C when you’re not home might seem like a good way to save money, it’s not always the most effective strategy. By using temperature setbacks, maintaining your A/C unit, improving your home’s insulation, and managing your electricity use, you can keep your home cool and comfortable while reducing your energy costs.

For the best results, consider investing in a smart thermostat and scheduling regular professional maintenance for your A/C system. By following these tips, you’ll be well on your way to a cooler, more energy-efficient summer in Tucson.

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