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How To Make a DIY Swamp Cooler

A step-by-step guide to building your own cooling system


I love building things myself, and you find there is always different ways you can build cool variations on standard items.

Yes, you could just go out and buy some boring type of air conditioning unit, but it is a lot more interesting to try to build a version yourself.

And I tell you what a DIY Swamp Cooler will have a lot fewer servicing costs as well!


What is a swamp cooler


It is a very fun and effective way to cool a hot dry room.

It also works out a lot cheaper than branded air conditioning units.

The swamp cooler is basically a storage vessel for cold water. In a dry and hot environment, the water will take on a large amount of heat, warm up, and evaporate.

This process takes the heat out of the room, and the temperature drops.

It also has the added bonus of making a really dry climate a little more hospitable.

You can buy proper mechanical versions of cooling systems that work on the same principle, but what’s the point… just make your own.

It is very easy to do.

Swamp Coolers may also be called: desert cooler, evaporative cooler, swamp box, and wet air cooler.


How to make a DIY Swamp Cooler: a step-by-step guide


Now you know what a Swamp Cooler is, lets build one.

Here’s how to do it:


What do I need for the swamp cooler


  • 1 Bucket = The bigger the room the bigger the bucket you will need. I usually use a 20L plastic bucket.


  • 1 Bucket Lid = you need to buy one that comes with its own tight-fitting lid. If the bucket doesn’t have a lid, all you are left with is a really large drinking device ha-ha.


  • Cleaning cloths = nothing fancy just the cheap bulk ones work great, look for a size of around 35/45cm * 25/35cm. Basically you are looking for a thin, porous cloth, again what you use here can be played around with, in regard to cost and porousness.


  • Glue = for the below glue gun that you will also need.


  • 1 Standard Desktop fan = I always buy USB fans for swamp coolers, but feel free to play around with the type of fan and design.


That is all that is needed to make your own cooling system. You will need some tools to actually make it obviously, hopefully you will already have these or can borrow them which will keep the cost down.


  • Dremel or sharp knife
  • Hot glue gun
  • Tape measure
  • Vernier


Making your DIY Swamp Cooler


Step one

Get the lid, find the center which is usually marked, and drill a pilot hole into it.


Step two

Get the fan, discard any stands etc you just need the fan, fan cage, and power supply.

Measure the diameter of the fan from the inside of the rim to the opposite inside.


Step three

You now want to mark the lid so you can cut a hole into the lid for the fan to fit into.

To do this, you use the pilot hole as an anchor point, and rotate the required size of the vernier around the pivot.


Step four

Cut out the hole that you have marked out, it should be dead centre in the lid and should fit the fan cage into it.


Step five

The fan cage is actually 2 identical fan cages screwed together.

Unscrew them.

Then take one half cage and place over the hole.

Mark where the screws will go.


Step six

Drill small holes through the lid for the cage screws to fit through.


Step seven

Now reassemble the fan with one of the half cages on top of the lid and one-half cage under the lid.

The fan is now suspended in the hole you made.

You want it, so that the electrical power wire runs under the lid as that will make the swap cooler look more professional and tidier.


Step eight

Cut a notch in the actual bucket where the wire naturally is settled. And run the wire out of the bucket, so it can be plugged in later.


Step nine

Now measure the halfway point of the bucket.

Then mark out a hole of 15cm on this halfway point.

Cut out the hole.


Step ten

Do this 3 more times, equally spaced around the bucket.

Basically, north, east, south, and west.


Step eleven

Get the cloths.

You need to cover the holes with the cloths from the inside.

So, glue the top of the cloth above the hole on the inside of the bucket securely.

Then glue underneath the hole.

The remaining bottom half of the cloth needs to be loose and able to touch the bottom of the bucket. If it does not get a bigger cloth, or glue 2 together.


Step twelve

Once the glue is dried, you can fill the bucket with cold water.

Until the water level is just under the hole you have made.

Then plug in the fan, switch it on, and you are done.

Congratulations you have a swamp cooler.


When, where and how to use your swamp cooler


The drier the better


Evaporative coolers work best in dry arid climates. The drier the air is the more effective it will be. As the cooling system works on the cold water absorbing the dry air and releasing cooler humid air.

The drier the air the quicker the water can evaporate, and the cooler your room will get.

If you already have hot humid air, the water will not be able to evaporate as efficiently. So, the room temperature will not drop enough to make a difference.

If humidity is regularly above 75% where you intend to use your swamp cooler, then you have picked the wrong cooling system. It will not work well, and it will probably make the situation worse.




As you know with industrial and car air-conditioners, for them to work you have to have all the windows shut.

The swamp cooler is different, the drier air the swamp cooler has the more water will evaporate and the cooler the air will be.

So, you actually need to have a means of supplying the swamp cooler with a constant stream of dry air, while letting evaporated water and therefore humid air out of the room.

Hence, you should actually open some windows. Maybe not have them swinging open, but just cracked a little. An inch should be enough.


Artificial dry air


We now know humid air is the enemy, so if you don’t want to open a window or if the bucket is too small to cool the room with the windows open.

Then a dehumidifier will help you out. A dehumidifier will take water out of the air, which means there will be drier air in the room and the swamp cooler will work better.

The closer the dehumidifier is to at least one of the holes the better, as long as you don’t block the air flow to the swamp cooler.




Get some houseplants that are native to hot dry climates in the wild. This is because they will have evolved to be able to suck moisture out of the air because they cannot always rely on getting it from the soil.

Cacti is a prime example of the type of houseplant you should get.

This will reduce the humidity of the air in the room, so that the swamp cooler can do its magic.




You want it placed somewhere that is as close as possible to where most people will be in the room for most of the time, so that they can get as much benefit as possible.

But for convenience and to ensure it is doesn’t keep getting knocked, then it needs to be in a sensible out of the way place too.

Basically, it is experimentation time. Place it in different places each day and see which you prefer.


How many?


One swamp cooler will cool one room, if it is a big room you will need a big bucket or multiple small buckets. This is not a whole house cooling system.


Keep it topped up


When you are about to use it. Top the water up to just below the holes. Let the cloth become saturated and see if you can top it up a bit more.

You don’t need to be constantly topping it up, but obviously if the bucket runs dry then it is just an empty bucket and it will be no good to you.


As cold as ice


Some people make one of two mistakes...


1) They add warm or boiling water thinking it will then be closer to the evaporation point. This does not work, as the water doesn’t then need to absorb the dry air to evaporate. So, the room doesn’t cool.

2) They recognise that the water needs to be cold to absorb as much as the hot dry air as possible. So, the use a load of ice, thinking the colder the better. This actually makes very little difference.


All you need to do is use standard cold tap water, and you will get the results you are after.


One of many


If you live in a changeable climate, then it is best to be prepared. So, you could have one type of cooling system for humid days and bring out the swamp cooler on dry days.

The great thing about a swamp cooler is if there is no water in it, it is really light to carry about, and can easily be stored away in a cupboard, shed, or garage.




You should swap out the water regularly, if you notice mold on the inside of the bucket or on the cloths then you should deal with it.

Simply clean the bucket with soapy water and/or replace the cloths.

Mold grows faster in humid conditions, but because you should only be using a swamp cooler in dry conditions, plus the fact I have recommended that you either have a fresh air flow or use a dehumidifier… then mold isn’t a massive problem.

However, you should keep an eye out for it as it can cause potential health problems.


The outdoors


Can you use it outdoors?

In a wide-open space… no.

But you can use it in a tent or a basecamp shelter for example. As long as you have a powerbank of some sort for the fan, or even better some portable solar panels. All you would need then is a water source like a river.

It could also be a useful thing for a prepper to keep in their bunker or food store.

Build one like I said but you could use the bucket as a storage container, until the time you needed it. Take out what’s in it. Fill it with water, hook it up to some power, and you are good to go.




You can buy swamp coolers and evaporate coolers, and there are a whole range of ones you can buy for a reasonable price.

But where is the fun in that.

Get your hands dirty so to speak.

I think it is always more satisfying to build something yourself, and increases your skill set.

It might not look as nice as a branded model; but you will gain a whole lot more satisfaction from looking at one you built yourself.

About Tom Bell

Hi - I'm Tom, the owner and founder of TheSurvivalSpirit.com! I'm a passionate outdoors enthusiast and am dedicated to bringing you the hottest online survival advice.  


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