Do you need to refill a swamp cooler or can you run it without water? In this article, we’re checking how a swamp cooler uses water to cool and what happens once it runs dry.
Contrary to popular belief you can run a swamp cooler without water! And in extreme situations, you can even refill a swamp cooler without access to water.
Let’s find out how!
Quick answer: Yes, you can run a swamp cooler without water. Once the water runs out, it becomes a simple fan. So, you still have a (reduced) cooling effect. In an emergency, where you don’t have access to water, you can collect morning dew by placing the water pads outdoors overnight. The humidity is enough to cool you in the afternoon heat.
Blogger’s bollox I found online
One more note from my side: I’ve just seen an article online claiming you can’t run a swamp cooler without water since the water acts as lubrication, and without that “lubrication” swamp coolers wear down.
That is totally wrong!
Reading these claims and seeing them ranked as the “best” result on Google gives me a headache.
Water does not lubricate a swamp cooler.
The wet water pads and the fan motor are completely separate components. They don’t touch!
The fan’s bearings are lubricated with oil. The water in a swamp cooler has nothing to do with lubrication.
If you lubricate anything with water, it actually wears down faster because of rust and limestone buildup.
Why do swamp coolers need water?
A swamp cooler is a fan that blows warm air from your room through wet sponges. The warm air causes the water to evaporate.
And this evaporation sucks away the heat energy from the air.
It’s as if you pour water into a hot pan. The water boils and evaporates. Meanwhile, the pan cools down.
That’s the concept swamp coolers are based on.
So, to work properly, the sponges have to be wet.
How to refill swamp cooler water
There are two main ways to refill swamp cooler water, depending on the type of unit you have:
Water Tank
Most swamp coolers have a built-in water tank. A water pump then draws water from that tank and soaks the sponges.
On average, a water tank lasts for 3-4 hours. Some swamp coolers can run on a water tank for 5-6 hours, but usually, these are just weaker models with less cooling power.
Continuous Refill
You can connect most (good) swamp coolers to a water source, such as a tap. Usually, the connection point is compatible with a garden hose.
Once connected, you can run your swamp cooler off the tap indefinitely and it will never run out of water.
Can you run a swamp cooler without water?
But what happens when you don’t have a water source?
As we just saw, you can always fill the water tank. A quality swamp cooler’s tank size is usually around 10 gallons. But, of course, sizes vary depending on the model.
10 gallons is quite a number. So, manual refills always become annoying after some time.
When you don’t have access to any water, you can run your swamp cooler without water.
Swamp coolers don’t overheat if you run them without water.
Just like regular fans, they are low-power devices and can run perfectly well without any water.
When you intentionally run your swamp cooler without water, disconnect the water pump’s power supply. Dry-running the pump wears it down quickly.
Some swamp coolers have a floater that detects water levels. When the water runs out, they will automatically shut down the swamp cooler.
Of course, the cooling effect is lower when you run your swamp cooler without water. It is comparable to the cooling effect of a regular fan.
Without water, a swamp cooler has nothing to evaporate. Therefore, it is simply a fan that blows air through dry pads.
Actually, to run your swamp cooler without water, remove the water pads from your swamp cooler for ideal airflow and lower noise.
Water pads only make sense when they are wet. Once they are dry, they are an unnecessary air resistance.
Also, since your swamp cooler doesn’t have to force air through the pads anymore, it runs quieter.
Alternative Method: Using Dew-Covered Water Pads
While running a swamp cooler without water won’t offer substantial cooling, there is an alternative method that some people use to make the most of dew accumulation.
By placing water pads outdoors overnight, they can accumulate dew.
In the afternoon, when the air is hot and dry, you can use the dew-covered water pads in the swamp cooler.
Of course, the dew won’t last you nearly as long as a full water tank.
Also, there’s another problem: Morning dew levels differ by US regions.
Ironically, in the dry and hot regions, where swamp coolers make the most sense, the average morning dew collected is the lowest.
| Region | Average dew collected (in millimeters) |
| New York City | 2.5 |
| Los Angeles | 0.2 |
| Chicago | 3.0 |
| Houston | 4.8 |
| Miami | 5.5 |
| Denver | 1.0 |
| Phoenix | 0.1 |
| Seattle | 2.2 |
| Atlanta | 3.3 |
| Las Vegas | 0.3 |
Still, morning dew collection might be worth it in an emergency even in the more humid regions.
Because, during the afternoon, air humidity decreases heavily. And then, swamp coolers work almost everywhere.
Coolers that don’t need water
Of course, there are cooling devices that don’t need water:
Air conditioners
Air conditioners, whether central AC units or portable air conditioners, don’t require water for their cooling process.
Here’s a list of my favorite portable air conditioners.
They operate by using refrigerants and compressors to remove heat from the air, providing effective cooling indoors.
Fans
Fans also work without water.
However, it’s important to note that fans do not reduce the temperature of the air.
Instead, they create a cooling sensation by blowing air over your skin, which carries away the heat from your body.
I always recommend floor fans, because they are very strong, run on low power, and are indestructible.
In principle, every swamp cooler is a floor fan covered in wet sponges.
Conclusion
Swamp coolers can run without water. Of course, running them with water makes a lot more sense.
The water evaporation is precisely what distinguishes a swamp cooler from other coolers such as air conditioners or fans.