Is It Bad to Keep Turning Your AC On and Off?

Find out if there’s any truth to this widely-held belief

Photo: SeventyFour / iStock / Getty Images Plus / Getty Images
Photo: SeventyFour / iStock / Getty Images Plus / Getty Images
Highlights
  • Turning an AC on and off doesn’t use as much energy as leaving it on nonstop and is less likely to damage the unit over time. 

  • Raising your thermostat to a higher temperature, investing in a programmable AC unit, and regularly cleaning the air filters are all ways to reduce AC energy costs. 

  • Letting an AC unit run all day is only recommended in extreme heat or humidity, which can cause damage to home elements like furniture or house plants.

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When it’s hot outside and the temperature in your home constantly fluctuates, stopping and starting your AC may seem like the right solution. If you’re hesitant to do so because someone once told you that it’s bad to keep turning the AC on and off, you might want to reconsider. The best plan of action depends on a couple of factors—like your local climate and the type of air conditioner you have. This guide will help you make the right choice and keep your home cool. 

Should I Turn My AC On and Off or Leave It Running?

A man turning the AC on in his living room
Photo: GoodLifeStudio / E+ / Getty Images

It’s commonly thought that turning an AC on and off over and over again uses more energy than simply leaving it on, but this isn’t necessarily the case. While it’s true that cooling down an especially hot house takes longer to do and requires a larger energy output over a shorter period of time, letting the machine run all day still uses more energy overall and is more taxing on the unit. 

Instead, leaving the AC off when you’re not at home and only turning it on when the temperature is no longer comfortable—unless the heat becomes unmanageable for pets or plants—will improve your HVAC system’s efficiency

Instances of extreme heat are the exception to this rule. If the temperature in your home begins to rise the moment your AC stops and the machine has to work twice as hard to cool it back down, you’ll actually use less energy by leaving it on. 

Another exception is the type of AC unit. Older and less efficient AC units require more energy to cool down the home, and smaller models like window units or portable units work harder to cool larger, overheated spaces when turned off and on frequently.

Impact of Frequent AC Cycling

Frequent AC cycling, or short-cycling, is different from just shutting off the AC when you leave the house all day. An AC unit should cycle two to three times per hour, but if your AC unit is turning on and off more frequently, it is short-cycling.

Short-cycling is a sign that something is wrong with the AC, such as a clog or a dirty filter. If the AC is short-cycling, it could lead to various problems, including:

  • Damage to the compressor

  • More wear and tear on entire AC system

  • Less efficient cooling and uncomfortable temperature fluctuations

  • Higher energy consumption and utility bills

  • Shortened AC lifespan

4 Tips to Lower Your AC Energy Costs

In addition to stopping and starting an AC unit as needed, there are a handful of other ways to keep energy costs down without sacrificing comfort. Use these tips to get the most out of your machine while using the least amount of energy.

1. Raise Your Thermostat if It’s Too Hot to Turn the AC Off

Best home thermostat temperatures for summer, with the optimal temperature when at home being 78 degrees Fahrenheit

If it’s higher than 100 degrees Fahrenheit outside and you’re about to head out for work, leaving your AC on during the day is probably the only way to ensure you don’t come home to a lava pit. Instead of letting the unit run at full power while you’re out, set your thermostat a few degrees higher than you would if you were home. This will help you use less energy overall during the day without making your abode totally uncomfortable when you return.

2. Invest in a Programmable AC System

It’s not too late, swap your current AC system for one you can program to turn on and off automatically. These options allow you to set the thermostat to your ideal temperature so the AC unit activates on its own when it’s too hot and turns off when it’s cooler. Plus, with a smart thermostat, you can control the temperature remotely.

3. Clean Air Filters Regularly

A woman removing air filters from AC unit
Photo: firemanYU / E+ / Getty Images

Running an AC with a dirty filter puts excess strain on the system, which can damage it and increase energy costs. Your unit has to work harder to cool down your house as more dust and debris build up in the system, which means it’ll need twice as long—and cost more—to do the same job.

Fortunately, it takes just minutes to change an AC air filter, and it has an immediate impact on your home’s air quality.

4. Schedule Annual Maintenance Checkups

Your AC unit will function better and more efficiently if everything is in working order, which is why it’s so important to hire an HVAC technician near you for a yearly checkup. AC tune-up costs range from $30 to $500 on smaller units and $350 to $750 for larger ones, though the price may increase if your tech finds major damage.

Frequently Asked Questions

Most units are designed only to cool the house down to 20 degrees less than the temperature outside. This means that if it’s 99 degrees Fahrenheit out and you’re trying to cool your home down to 65 degrees, you’ll notice your AC is struggling. 

Lower the blinds on all your windows, turn on your ceiling fans, and keep the thermostat at a consistent temperature to help your AC do its job. Investing in an HVAC maintenance plan also helps because pros will come out to inspect and tune up your unit regularly, keeping it in optimal working condition.

AC repairs cost $350 on average, but the total can vary from $100 for a refrigerant recharge to over $3,000 to replace a compressor. The cost will depend on the extent of the repair and what type of AC you have, plus whether your HVAC system is under warranty.

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