Okay, you live in a region that’s hot and dry.  Arid is another way you can describe it.  Regions like the American southwest or the Mediterranean.  There isn’t a lot of humidity but when it’s hot, it’s nice to have an appliance that can cool things down and keep your spaces comfortable.

What kind of appliance do you have to accomplish this task?  Well, for those kinds of regions, a swamp cooler (or evaporative cooler) is often the most common, most efficient, and most effective appliance you can use.


Basically, a swamp cooler removes the heat from air by passing it over pads that are soaked with cold water.  The water traps the heat and the air evaporates the water.

As a result, you get cool air that’s more humid, combating the uncomfortable heat and dry air that comes in a region that’s hot and arid.

But sometimes your swamp cooler may not be blowing cold air the way it’s supposed to.  It may be circulating air but for some reason, it’s not removing the heat and providing cool, humid air.

If this is what you’re dealing with, let’s take a look at a couple of reasons why your cooler may be acting this way and what you can do to get it operating the way it should.

1.  What Mode Is Your Swamp Cooler In

Before going to deep into why your swamp cooler isn’t blowing cold air, let’s take a look at your swamp cooler and if it has different operating modes.

Yes, different operating modes.

Not all swamp coolers operate in cooling mode automatically, especially portable units.  You can turn the power on and the fan will kick on, but it doesn’t mean your unit is officially cooling.

If your unit is outfitted with a COOL button, you need to press it for the water pump to kick on and officially soak the membrane as designed.  After a small amount of time, you should feel cool air start to be produced.

Different Portable Swamp Cooler Models
Not all swamp coolers mediately switch to cooling mode when you turn on the power.

2.  Is Your Swamp Cooler Getting Water?

Remember, the big thing that makes a swamp cooler effective at cooling is cool water.  So, if you’re not getting cold air out of your cooler, it’s time to also check the water supply.

If you’ve got a swamp cooler for your whole house, you probably already have a water supply line piped to the unit.  At the very least, you more than likely have a hose connection to your unit.  In either case, make sure the water supply is on in accordance with your manufacturer’s recommendations.

On the other hand, if you have a small portable swamp cooler, you usually have to refill the installed reservoir by hand.  So, in this case, make sure your reservoir is full of cold water.

3.  Check Your Pads

Perhaps you’ve got a good water supply or your reservoir is topped off with cool water.  If this is the case, and before you assume the pump has issues, take a look at your water pads.

When you look at the pads, you’re looking to see if they need cleaning or replacing.  The reason is, over time, pads can deteriorate and lose their ability to retain enough moisture to work to remove enough heat from air flowing through them.  Basically, the evaporative process becomes incomplete.

If the pads aren’t holding enough water, it’s probably due to dirt, age, or both.

Often, it’s easier to replace the pads.  Usually, manufacturers recommend replacing if pads are old and damaged, or on a periodic basis no matter what.

4.  How’s the Quality of Your Water?

It’s not uncommon for household potable water to cause build-up in any appliance or plumbing fixture.  The same is true for swamp coolers.

If you’re dealing with a cooler not blowing cool air, you should also check to see if you have build-up.  You should first see evidence of it when inspecting your pads.

Instead of dirt or damage, maybe you see white calcium build-up or algae.

If it’s algae, you should also notice a distinct odor when operating.

Now, if you’ve got build-up on your pads, you may also have build-up elsewhere in your unit.  So, look for build-up and clean where you can, especially in areas where the flow of air can be interrupted and cause inefficient heat transfer.

5.  How are the Water Pump’s Electrical Connections?

Where there’s water, there are often issues with corrosion.  Your electrical connections should be routinely inspected even if you’re not having issues with your cooler.  Catching a problem early can avoid equipment ineffectiveness and prevent possible damage down the line.

When it comes to a swamp cooler not blowing cool air, there’s a strong chance something’s wrong with the water-side of the unit.  So far, you’ve run down the lists of most of the easy to fix issues that can be addressed right away.

Now it’s time to take a look at the water pump and its motor.  First, you need to inspect the electrical connections.

Are there loose wires?  Are there disconnected wires?  Any visible damages to the wires?  Any dirt or corrosion at the connections?

If you have any of the above issues, you probably have a pump that’s not operating properly, which would absolutely impact water supply to your pads.

Loose wires can be tightened and disconnected wires can always be reconnected.  Damaged wires can be replaced.  Dirty and corroded connections can be cleaned with rubbing alcohol or sandpaper.

All four can be done by you, however, if you don’t feel comfortable with the DIY-aspect of electrical maintenance, feel free to call a technician.  As always, safety first.

6.  How’s the Water Pump?

Swamp Cooler Water Pump System Properly Installed
The water pump circulates water through the system and wet the cooling pads.

If you’re confident the water pump’s electrical connections are good, then you may have a water pump issue.

Issue as in it’s not working anymore, regardless of the connections.

Now, it could be a simple as a pump that needs cleaning.  Pumps do push water and if something is impeding the pumps ability to rotate and move water, it’ll stop working and the motor should shut off.

Most coolers have a built in feature that will shut the whole unit down if the water pump isn’t functioning.  It’s the same type of safety feature that’ll shut down a cooler if the pump or motor overheats to prevent damage.

That doesn’t mean it always works that way.

So, it could be a case the pump was damaged in some way and your unit is still able to move air but not cool it.

If you have a pump that’s not working properly, you probably need to remove it, clean it, repair it, or replace it. 

7.  The Fan or Belt

With all this talk about water, should you inspect the fan and the belt for the swamp cooler?


If your swamp cooler is blowing warm air, it’s safe to assume air is passing through the unit, which means the fan is moving air and the belt is rotating the fan.

But because you are trouble shooting your swamp cooler, it never hurts to inspect the fan, it’s electrical connections, and the belt’s tension as part of normal maintenance.

If the belt is loose, your unit is moving air but maybe not enough to evaporate the water in the pads.  A properly tightened belt may be the simple fix you’re looking for.

8.  Supply Air

Oh, and while you’re at it, make sure the swamp cooler has a good source of supply air.  You should already know this if you’re not a swamp cooler rookie.

But, to review, a swamp cooler should always have enough room around it to draw enough volume of natural air.  It also never hurts to position it near an open door or window where it can catch a breeze.

Bad air flow means a lack of cool air, just like a loose belt does.


If you’ve got a swamp cooler that’s blowing air but the air isn’t cool, it’s may be an issue on the water supply side of the cooler.  In that case, there are about six things to check out:

  • Cooling Mode Selected (if it’s an option).  If your cooler has this mode and it isn’t selected, the fan may operate but the water pump will not turn on.
  • Water Supply.  Is the water on if a supply line is connected?  Is the water reservoir full if the cooler is hand-filled?
  • Water Pads.  Are they dirty, damaged, or covered in build-up?  Do they need to be cleaned or replaced?
  • Build-up.  Has build-up from your water spread to other parts of the cooler, impacted air flow and heat transfer?
  • Water Pump Electrical Connections.  Are the electrical connections for the water pump damaged?  Or are they loose?  Are the connections clean and free of corrosion?  Do they need to be repaired or replaced?
  • The Water Pump.  If it’s not moving water, is it bound-up or seized?  Has the motor overheated and burned up.  Does it need to be cleaned, repaired, or replaced?

Don’t underestimate the air flow side of the cooler, as well.  Remember, swamp coolers rely on both natural air and water supply to produce cool humid air.  So, if you’re checking for problems on the water side, also check the air side, specifically:

  • Belt Tension.  If it’s too loose, you may have poor air flow, incomplete water evaporation and heat transfer.
  • Natural Air Flow.  If the cooler doesn’t have access to enough natural air, the fan will not draw enough air into the unit to complete the evaporative process.

If none of these are the causes of your cooling issue, it’s probably time to contact a service center or technician for help.