Can I Run My Swamp Cooler All Day?

Today is going to be a scorcher! You want to stay safely out of the sun and indoors, which means you need a reliable cooling source. What about your swamp cooler? Can you run it all day or only in short bursts?

If you don’t mind refilling the swamp cooler with water several times, then you can run it all day. A continuous fill swamp cooler or using your cooler on lower speed settings are two great ways to lessen how often you need to fill the cooler when running it for hours at a time.

In this article, we’ll talk more about the implications of running your swamp cooler all day, including how much you can expect this to cost you. We’ll even provide some tips for increasing the coldness of your swamp cooler, so make sure you keep reading!

Should I Run My Swamp Cooler All Day?

As a refresher, swamp coolers suck up warm outdoor air and then pass the air through soaked evaporative cooler pads. The air that comes out of your swamp cooler into your home is then nice and cold. Thus, as long as there’s hot air outside, you might figure why not run your swamp cooler?

Well, because your swamp cooler needs water to operate. The water supply valve in your home attaches to the swamp cooler. The pump, which is at the bottom of the cooler, sends water through water distribution lines so the evaporative pads stay wet.

The longer you have the swamp cooler on, the faster it will blow through its supply of water until there’s nothing left. Should the evaporative pads dry out because they don’t have a source of water, your swamp cooler won’t work.

If you’re going to stay home all day, then it’s not such a big deal to have to refill the reservoir with water a few times. However, if you’re spending a day at the pool or the beach and you’re only leaving the swamp cooler on for the benefit of your cat or dog, it’s not like your pet can refill the cooler themselves.

This means they only get a finite amount of time with the cool air running, then it’s back to the stifling heat. For some animals, that can be deadly.

Fortunately, it doesn’t have to be an all-or-nothing type of scenario. You have a few options for lessening how much water your swamp cooler requires if you want to run it for hours at a time.

Don’t Use the Swamp Cooler All Day

This is the most obvious solution. The swamp cooler can preserve water when it’s not running as often so you can safely leave your pets for an afternoon or even the entire day. As for which times are the best to run the swamp cooler selectively on a hot day, we’ll talk about that shortly.

Reduce Operating Speed

The slower your swamp cooler runs, the less water it will need. However, operating at reduced speeds does mean the air won’t be quite as cold as it would if the cooler were running at a higher speed. Later, we’ll provide some pointers for increasing the coolness of your swamp cooler, so you’ll certainly want to check that out.

Upgrade to a Continuous Fill Swamp Cooler

Your other option is to buy a swamp cooler with continuous fill settings if you don’t already own one. One such example is the Hessaire MC37M portable evaporative cooler. This swamp cooler can bring down the temperature in areas of up to 950 square feet. It cools at a rate of 3,100 cubic feet a minute.

If you’d rather, you can use the manual fill setting or you can set the Hessaire for continuous fill. When in this mode, you’ll need a garden hose or another household hose. Connect the hose to the float adaptor, which will tell the swamp cooler when it’s full so it doesn’t keep overfilling with water.

How Much Does It Cost to Run a Swamp Cooler All Day?

It’s just too hot to forego cooling today, so you’re thinking you’ll probably run your swamp cooler all day. You’re admittedly pretty nervous about what your utility bills will look like. How much are you going to spend?

Well, that depends on which evaporative cooler you own. If it’s a Hessaire like the continuous fill swamp cooler we mentioned in the last section, then using this cooler might cost you $0.01 to $0.04 an hour.

As a general estimate, it might cost you $2 to run your swamp cooler for 24 hours. That’s hardly going to impact your monthly bills, as $2 is less than what you’d spend on a cup of coffee these days!

At that rate, let’s say you wanted to run your swamp cooler for a whole month and still on a 24-hour basis. That would only cost you $60, which is very affordable for most people.

If you were to use a central cooling air conditioning system for the same period, you might spend upwards of $330. Swamp coolers are far more cost-effective, so if you must run yours all day, you don’t have to worry about skyrocketing utility bills.

If Only Using a Swamp Cooler Selectively, What Are the Best Times to Run It?

You want your swamp cooler to last you for years to come, so you’d prefer to not strain it so much during the dog days of summer. Since we recommended using the cooler at certain times, you want to try that. Which times of day are ideal for running your swamp cooler?

First Thing in the Morning

If you’re used to getting up with the sun because you like to hit the gym before work or you just appreciate the extra time, then as soon as you’re awake, turn your swamp cooler on.

True, it’s not really hot out, at least not yet, but the cold air the swamp cooler uses now will be all the colder later when you really need it.

The Middle of the Morning

Maybe you just can’t drag yourself out of bed at first light no matter how hard you try. That’s okay. If you can turn your swamp cooler on before 10 a.m., you’re still in the clear. Just be aware that the air that’s pulled in from the outside may be more laden with pollen and other allergens that can trigger symptoms in some allergy sufferers.

For that group, we recommend turning on your swamp cooler early in the morning or later in the evening.


The afternoon, being the hottest part of the day, is not a great time for using your swamp cooler. Once the sun begins setting and the temperatures come down, do make sure you turn your swamp cooler back on. You can also combat the heat that comes from the kitchen as you begin prepping dinner.


Another option for those who don’t have the time or inclination to wake up early in the morning to turn on their swamp cooler is to leave it on overnight. This will ensure you wake up to a cool house.

Tips for Making Your Swamp Cooler Even Colder

If you can maximize how much cold air you get from your swamp cooler, you might not have to worry about running it all day. Your home will be comfortable enough that you can relax, sleep, and enjoy yourself.

How do you increase the cold output from your swamp cooler? Try any of these tips!

Keep It Clean

A gunked-up swamp cooler can’t pull in air as efficiently, nor release it. The quality of the air might also be questionable.

Every now and again, you want to check the evaporative cooler pads for mold and mildew. Look for cracks as well and then dispose of damaged pads. Since the cooler pads are a major component of a swamp cooler, if they’re not working their best, neither will the cooler itself.

Although you just add water to the reservoir, it can still get dingy. Squirt some dish soap in a container of water and clean out the inside of the tank about once a month and certainly a few times per season.

Take out the fans and air intake grills. If these are dusty or dirty, vacuum them. Don’t forget to wipe down the swamp cooler exterior with dish soap and water.

Don’t Run the Cooler During Peak Hot Hours

Although swamp coolers are designed to take hot air and make it cold, the hotter the air, the less your swamp cooler can do. That’s why we told you to avoid running your swamp cooler in the afternoon. You’re only breaking even with the temperature, not really cooling your house.

Pour in Cold Water

Here’s an easy way to instantly feel the relief of cold air from your swamp cooler. The next time you go to refill the unit, pour cold water. Aim for temperatures around 50 degrees Fahrenheit for best results.

No, there’s no need to buy a thermometer for the kitchen tap. The water that comes out of the tap when you turn the cold faucet on is usually around 50 degrees anyway.

But Skip the Ice

Okay, so if cold water is good, ice is even better, right? Actually, no. Water at around 50 degrees or warmer, such as lukewarm water, is all the swamp cooler needs for a slightly enhanced cooling effect. Once you use water that’s around 40 degrees or even 30 degrees, the benefits are negated.

Why? Ice isn’t liquid, so it has to melt. Then the swamp cooler can evaporate it. In the meantime, you’re sitting and sweating, waiting for your swamp cooler to get to work. It’s not worth it.

Prime the Evaporative Cooler Pads

Speaking of waiting, did you know the average amount of time it takes for your swamp cooler’s evaporative cooler pads to be fully saturated is 15 minutes? When you’re already sweating, that can seem like an eternity. By pre-wetting the pads, also known as priming, you can save that precious time.

Reduce Humidity

Evaporative coolers work best in dry conditions, so lessening humidity in the house is a great idea. Some indoor plants naturally dehumidify, as does a dehumidifier. Don’t just put the dehumidifier in the house though; set it up by the air intake grill of your swamp cooler.

Open a Window or Two

The fresh air that comes through your open windows provides a consistent source of warm air for the swamp cooler to pull from. You don’t need to open your window fully, which we’re sure you don’t want to do on a hot day anyway. An opening that’s an inch or two will make a big difference in the performance of your swamp cooler.

Final Thoughts

You can run your swamp cooler all day should you so choose without seriously increasing your monthly utility bill. However, you will need to be available to refill the reservoir in the interim. Should you not want to do that, run your swamp cooler first thing in the morning or overnight to fill your home with cool air. You can also use a continuous fill swamp cooler. Best of luck!


Geoff Southworth is the creator of, the site that helps new homeowners, investors, and homeowners-to-be successfully navigate the complex world of property ownership. Geoff is a real estate investor of 8 years has had experience as a manager of a debt-free, private real estate equity fund, as well as a Registered Nurse in Emergency Trauma and Cardiac Cath Lab Care. As a result, he has developed a unique “people first, business second” approach to real estate.

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