Can You Leave A Window Air Conditioner On 24/7?

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If you live somewhere where it's hot and humid, it might be hard to keep a comfortable temperature in your house without central air. But central air is expensive and takes a lot of upkeep. If you're stuck depending on a window air conditioner, sometimes it seems like it's running non-stop. But is this safe? Will it wreck your machine? We've checked with experts on window units to let you know whether you can leave a window air conditioner running 24/7.

If you can afford the energy cost, there's no real harm to the machine to keep it on. It can run as long as you want or need it to. But, for several reasons, running a window A/C for a long time is actually less effective than turning it off and back on later. And it's never a good idea to leave the A/C on when no one is watching it. If your compressor hits a power surge and you aren't there to turn it off, you can burn it up completely.

Keep reading for more information on why you can run a window A/C all day. But, more importantly, we'll cover why you maybe don't want to. This article will explain why and when it's best to turn the air conditioner off for a bit and start it up again later. We'll also cover how to take care of your window unit and when and how you should clean it. Finally, we'll explain how long your unit should last and how to troubleshoot it if it's not performing as well as it used to.

Exterior of a wooden barrack with a sliding window and an air conditioning unit, Can You Leave A Window Air Conditioner On 24/7?

Is It Safe To Run A Window A/C Unit All Night?

There's no reason you can't run a window A/C unit all night long. The only real obstacle is the electricity bill. If you can afford the energy costs, you can certainly leave your A/C unit running if that's what it takes to maintain a comfortable temperature.

There are no parts or components in the air conditioner that overheat from running too long. And the air conditioner won't slow down or perform poorly after it's been left on for a while. However, it is worth noting that issues such as an electricity spike can damage the A/C if it's unattended. For example, an energy surge can affect the compressor.

If you trust that an issue like this would wake you up so you can turn the unit off before it's damaged, there's no problem. But if you're a heavy sleeper or the unit is in another room, it might be best to turn it off before bed. If it continues to run all night while the unit is compromised, you can eventually burn the compressor out altogether.

What Happens If A Window A/C Unit Runs Too Long?

Technically, you can run an air conditioner as long as you want. But, an air conditioner left on all the time does pose a few problems. Most people set their A/C for a specific temperature. Once you reach this temperature, the unit stops actively cooling for a while even though it remains on.

An air conditioning unit photographed outside an apartment building

An air conditioning unit staying on all day, starting or stopping frequently whenever it's out of an ideal temperature range, uses more energy. It also works less efficiently to dehumidify the air. If you're concerned about either of these things, it's actually more effective to let the air conditioner run until you're ready to turn it off. Then, let it rest for a while and turn it back on when it gets too hot.

It isn't a problem for the A/C to be on all day; it's just not ideal for most people's electric bills. It's also worth noting that an A/C running when it isn't needed does leave an environmental footprint. Hydrofluorocarbons (HFCs) are released when these units are used, a big contributor to global warming. If you don't need the A/C on to keep the room at a liveable temperature, do Mother Earth a favor and give it a rest.

Do Window A/C Units Need Maintenance?

Window A/C units are a bit simpler and less expensive than a whole-house system. For example, a window unit doesn't need the regular maintenance and technician's care that a central air system does. But this doesn't mean that it's maintenance-free.

If the unit gets regular use, clean the filter about once a month. You can go a little longer between cleanings if it's not often in use. This isn't very hard - just remove the filter and let it soak in warm soapy water. Rinse all the soap and gunk off until it's clean, let it dry, and put it back in your unit.

Dirt accumulated by the air conditioning unit

It's also a good idea to remove the unit if you won't need it for a few months. It lasts longer and performs better, which might give you enough incentive to lug the big heavy thing out of the window. It's annoying but better for the machine.  Just set it aside somewhere out of the way, with a cover to keep out dust.

Once A Year Maintenance

The following items are things that you need to do occasionally to keep your unit in good shape.  Once a year is fine in most cases. For ease, consider doing these things before you install the unit every year - or when you take it out of the window at the end of the season.

Clean The Fins And Fans

There are two coils on a window unit, one in front and one in back. These coils are covered with fins made of delicate aluminum. These can get dusty, dirty, and even start to grow mold.

Accumulation of dirt in the fans of the air conditioning unit

When the unit is out of the window, take it outside. Mix water and a few drops of detergent in a spray bottle. Spray the fins with this mixture - both in the front and back of the unit. Use a soft bristle brush to gently clean and remove the dirt. When they're clean, you can gently rinse the fins with a hose.

There are two fans and a blower near the evaporator and a bladed fan by the condenser. Use the same spray bottle of water and detergent to clean these, scrub gently, and rinse. Don't worry about getting the machine wet - the electrical parts are sealed and safe from water.

Check For Bent Fins

The design of the fins keeps them apart from each other. But it's easy to bend them and accidentally have fins touching each other. This will keep your unit from working as well as it could.

Check your unit over for bent fins. If you see any, you can fix it. There is a special tool for this, called a fin comb. It's a bit easier and faster to use the comb.

Click here to see this fin comb on Amazon.

But if you don't want to get a special tool, you can also use a credit card. Just insert the card into a gap where the fins aren't bent. Slide it down until you get to the bent section, then pull the fins apart gently with the card, unbending them. It takes a bit of time and patience, but it's manageable.

Check And Empty The Drain Pan

Underneath the coils is a drain pan. This collects condensation as it drips. Drain out the dirty water from the pan. Also, check over the drain hole. If there's any debris plugging it, the water can back up.

How Long Should A Window A/C Last?

A window unit can typically last eight to 10 years. If yours hasn't made it this long but doesn't seem to be cooling like it used to, start with some basic troubleshooting. Check to make sure the seal is good and not letting warm air in. Check and clean the filter, as explained above --dust off the coils. If the unit still isn't meeting expectations, it might be time to replace it.

In Closing

A window A/C unit can run for as long as you need to reach a comfortable temperature. Just keep in mind that a unit that starts and stops when it reaches a set temperature actually uses more energy and removes humidity less efficiently. Sometimes it's better to cool the room and then turn the unit off for a while. When the room becomes uncomfortable again in a few hours, repeat. Your electric bill,  and the environment, will thank you.

And don't forget to clean your filter about once a month and perform other regular maintenance yearly. This will keep your window A/C in top shape for the full lifespan of eight to 10 years.

If you enjoyed this article, see:

How Many Square Feet Can A Ductless Air Conditioner Cool?

6 Types Of Air Conditioners

This Post Has One Comment

  1. Mouse

    Thank you. I had a couple questions and was looking for some answers about our window A/C unit. It’s only about 4 years old now and isn’t causing any problems, I’m just retired and have too much time to think about things.

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