How Long Can You Leave A Window Air Conditioner Running?

Are you one of those people who have money to burn? Your presence here and the fact that you’re concerned about how long can you leave a window air conditioner running suggests otherwise. But that is far from being the only thing this question reveals.

It also tells us that you live in a scorching and humid environment. That it is almost impossible to turn off the air conditioner and have a comfortable indoor temperature in the area that you live. The weather outside is too hot for you to remain sweat-free under a running ceiling fan.

How Long Can You Leave A Window Air Conditioner Running?

Experts tell us that it is safe to have your window air conditioner running 24/7. No part inside the air conditioner will get too hot and melt if you keep it running all day. The performance of the air conditioner, too, won’t suffer if you forget to turn it off.

Having said that, most people still run their AC in intervals. That means that after keeping it running for, say, three hours, they turn off the AC before turning it back on in a few hours. Ever wondered why that is the case? Let us explain.

Here are four reasons why running your AC all day is a bad idea:

#1: It will consume more energy

It will consume more energy

As you might already know, air conditioners, after running for some time, achieve the temperature which you’ve set their thermostat to achieve. That causes the thermostat to send a signal to the AC to tone down, causing the air conditioner to trip. That is where things start to get costly.

As your ac alternates between tripping and running at full speed, it consumes more energy than a unit that is running at full speed all the time. That is because the latter scenario involves minimal disturbances (tripping) to the AC’s performances, whereas the former scenario is more start-stop.

Consequently, if you’re worried that your ac might drive your monthly electricity bills north, make sure to turn it off every few hours. Apart from saving you a fair amount of money, the air conditioner, once it’s back on, will run more efficiently than if you have allowed it to run continuously.

#2: It will be less efficient at dehumidifying your indoor air

Most of you will already know that air conditioners dehumidify indoor air. Those who don’t need to decipher their functioning to understand this point. Air conditioners work by taking hot air from your room, passing it over the condenser, and then expelling the heated refrigerant outside.

As they do that, air conditioners also draw in moisture from the room and thereby end up dehumidifying it. This process is crucial as it improves your comfort levels, reduces the chances of moisture-loving allergens thriving in your indoor air, and eliminate that smell that emanates from damp spaces.

The abovementioned process doesn’t happen at its most optimum level if you keep the air conditioner running all day. That is because ACs are better at humidifying when they are going at full speed – which they only do if you run them in intermittent intervals.

#3: It will hurt the environment

It will hurt the environment

There is no denying that air conditioners are bad for the environment. The hydrofluorocarbons (HFCs) that they use to bring down the temperature of the outside air before sending it into your room are one of the biggest contributors to global warming.

Does that mean you should skip air conditioners altogether to save the environment? You might not if the weather is searing out there. What you can do, realistically, is turn off your air conditioner once it has brought the temperature in your room to a comfortable level.

That is because the carbon emissions from air conditioning are dependent on the time you leave it running. While a 1.5-ton ac that keeps running throughout the day emits 5344 grams of carbon, another that runs 8 hours emits only 222g. You can do your part for the environment by turning off your AC.

#4: It might be dangerous if left unattended

Assume a scenario in which you have left your ac running before going to the office. You thought that in the hot weather that is out there, you’d be greeted by a cold room once you’re back. Little did you know that an unattended running window air conditioner can pose complications.

For instance, if there’s an electricity spike in your area when the ac was running, it could hurt its compressor. Sure, the same would happen even if you were home, but you’d then be able to turn off the air conditioner to prevent its compressor from further damage.

However, since you’re no longer home, any electricity spike can hurt the compressor and might even end up burning it in the worst-case scenario. Professionals tell us that it’s an expensive problem as the compressor is one of the most expensive parts in an air conditioner.


Running your air conditioner 24/7 won’t do any damage as long as you’re present on the occasion and have the bank balance to pay the astronomical electricity bill that will come at the end of the month. But that doesn’t mean that there aren’t any shortcomings to this approach.

As we have stated earlier, an air conditioner that keeps on churning out cold air is less efficient than one that operates in intervals. Also, it will be less efficient at dehumidifying your indoor air, leading to problems like moisture-loving allergens thriving in your indoor space.

If that wasn’t worse enough already, a 24/7 running air conditioner is bad for the environment. Its carbon emissions directly contribute to global warming and, in turn, the rise in global temperatures. That starts a cycle where the more the outside temperature goes up, the bigger will be your air conditioning needs.

Therefore, if you want to enjoy the offerings of your window air conditioner in a guilt-free manner, we recommend that you turn it off every few hours. You can get in touch with us if you need further proofs as to why this approach is better than keeping your ac running all the time.

7 thoughts on “How Long Can You Leave A Window Air Conditioner Running?”

  1. I have COPD and run my AC 24/7 unless it drops below 70 outside and even in the winter I have it running most of the tlme. I live in an apt. I’ve been here 5 yrs. and had 2 new ones put in because they stop cooling. I clean the filter the second I see the light. The unit is an LG not sure of the BTU wall unit. Small unit. How many hours should it last? It has to be cool or I can’t breathe.

  2. I am always thoughtful about when to turn on my AC and for how long. I am aware of environmental concerns and it has to get pretty warm before I will go to my AC over my fan. We recently had a strange weather event in my area where temps were 110 to 118 for a couple days which is unheard of where I live. At these temps I had thought for just one entire night could I run my AC safely as the overnight low was 88 and this was at 5am. I asked the internet and this site pulled up and the tone was poop, truly and dearly poop. I was asking a simple question I did not need a lecture. That said I think the author had good intentions somewhere in this message.

    • Inland SoCal we run the ac 25/8 6 months a year. #bakersfieldCApride 110Degrees kiss my glass you fog breathing hypocrites lol lol

  3. If it’s so hot you needtorun it temporarily 24/7 to get through a heat spell, it’s okay to do that. If you live where it’s 85 degrees and you can open a window at night, more power to you. Don’t waist energy, and don’t be a earth devouring tennis-playing Montypython blancmange but the window units, when used to cool small concentrated areas of the house, and if only those rooms are needing cooling,are much more friendly than running an entire central ac unit, and running it for 8-9 hours during a temp peak period each day and shutting it down when it cools down at night and during less extreme normal days is something you should not feel guilty about.

  4. Hi Anna, my name is Patti K Welder, and I live in South Texas. After reading your comment I can only assume you live up north or in Canada, as it has been having unreal hot temperatures like we have down here all the time. I am disabled I suffer from acute chronic pain I fell off a 100 foot cliff 33 years ago and broke 28 bones in my body From the neck down. 15 years ago we used to have central AC and our bill was seven to $800 a month. When it went out we switch to window units, we have a small medium size in the living room one in my bedroom/office which is fairly small and one in my husbands bathroom which is fairly small. They are in expensive they’re only $200, as they need replacing every 2 to 3 years but our bill is now only $200 plus a little maybe give or take. How well I understand the hot weather you have been going through, but thankfully you did not get the humidity like we have down here So close to the Gulf of Mexico. And needless to say I live in chronic pain that this humidity and pressure constantly changing just makes my body throb, I can’t begin to tell you. But I can tell you this I run my air conditioner full-time at about 71° for the simple fact if you turn it off for 10 minutes you’re up to 85 or 90° just inside the house, and that really sucks. I am 62 years old now so I’m currently writing the true story of my Texas dynasty! You will know when it’s out for sure as it will be well advertised. You can always find me on Facebook if you do social media Patti Welder in Victoria Texas. And you can always Google our family that is how well known our family is in the dynasty that I come from and I’m the only one left alive now so all I can tell you, My family is so scandalous that I sweat bullets with my air conditioner on lol, and never go hot! And I did have found sometimes I put a fan in front of my ax unit just in case, When you get my age you sleep a little harder sometimes! You take care and you run that unit whenever you’re hot! Creature comfort is definitely something the human body needs,, an AC is part of that. I hope your weather stables out soon, as we are always on the watch for hurricanes where I live. Take care and God bless sincerely Patti, from Texas❤️👸🏻

  5. My air conditioner runs for a total of 10-12 hours. It has been going on in the same way for 6 long years. The device did not have any problems. My question is, can there be any problem if it is running too much?

  6. Absolutely! No part inside the air conditioner will get too hot and melt if you keep it running all day. The performance of the air conditioner, too, won’t suffer if you forget to turn it off.


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