Introduction: Mega Swampy: a Large, Economical Swamp Cooler Powerful Enough to Cool Multiple Rooms!

Hi, in this Instructable I will be showing you how to make a large, efficient, and economical swamp cooler powerful enough to cool most of an average suburban home.

Over the past few weeks, the temperature in my hometown has regularly topped 100 degrees, even reaching record-breaking heights on several occasions. My house does not have air conditioning. This has made for a rather hellish experience during these weeks. So, I got to thinking about how to cool off. I immediately discounted buying/building a conventional air conditioner, because I have neither the hundreds of dollars required to buy one, nor the knowledge required to build one. Then, I remembered that my mom had come home from playing roller derby one day during the height of the heat wave saying about how it had gotten so hot that Rose City Rollers had rented a bunch of swamp coolers to cool off the roller derby arena. I thought "Now there's an idea..." and, after looking at a few diagrams of commercial swamp coolers, decided to build one for myself. What I ended up building was far more powerful than I expected, able to cool not only my bedroom, but also most of the rest of my house, adding up to a total of about 2,000 square feet of floor space being cooled by 20-30 degrees Fahrenheit. The only downside to the unexpected level of effectiveness was that I was denied the opportunity to gloat to the rest of my family about having the only air-conditioned room in the house. As I am sitting here writing this right how, the outside temperature is 94 degrees Fahrenheit, my swamp cooler is sitting on top of the dresser next to me, and the house is a comfortable 67 degrees. So, let's get started!

Step 1: Parts List

Here's what you'll need:

  • 1 - 23" 2x4
  • 4 - 16" 2x4
  • 2 - 13" 2x4 w/45 degree angled end (wait to cut these out, I will explain what I mean later)
  • 4 - 3 1/2" 2x4
  • 2 - 16" by 24" 3/8" plywood
  • 1 - 26" by 16" 3/8" plywood
  • 1 - 26" by 24" 3/8" plywood
  • 2 - 26" 3/4x8 (I think they sell them as 1x8s)

For a simplified wood shopping list, you need to buy 2 8' 2x4s, 2 2'x4' sheets of 3/8" plywood, and 1 8' 3/4" 2x8.

  • 2 - 19" 3/4" PVC pipe
  • 1 - 15 1/2" 3/4" PVC pipe
  • 1 - 13" 3/4" PVC pipe
  • 2 - 2" 3/4" PVC pipe
  • 1 - 4" 3/4" PVC pipe

Simplified: buy 1 8' length of 3/4" PVC pipe.

  • 6 - 90 degree 3/4" PVC pipe elbows
  • 1 - 3/4" male threaded to unthreaded PVC pipe adapter
  • PVC cement
  • 1' of 1/2" poly drip irrigation tubing (home depot usually has rolls of the stuff that you can buy by the foot)
  • 2 - 3/4" female hose thread x 1/2" poly drip irrigation tube compression fit swivel adapter
  • 1 - 13" fan (or any similar fan, you will be cutting a hole to insert the fan into, so if your fan is a different size or shape, just cut a different hole)
  • 1 - submersible utility pump (Get the cheapest one available, all of these pumps fall into the category of extreme overkill for this project, all of them will move water at a much higher rate than we really need, however I have found that having fast-moving water discourages algae, mold, and other junk from growing in the cooler. Also, this way, if your basement floods, you will have a pump capable of getting rid of the water in a timely manner. Actually, the pump I used was bought for exactly that, and had been sitting around being useless and taking up space ever since until I turned it into a swamp cooler.)
  • 2 - 24" by 36" Cut-to-fit air filter pads (or swamp cooler pads, but actual swamp cooler pads do not improve performance enough to justify the massive increase in cost, and they're a lot harder to find depending on the area you live in)
  • 14 gauge galvanized steel welded wire fence (you only need a few feet of it, so buy the smallest roll available, and use the rest for tomato cages or something (like a FENCE! But here at instructables, we all know that it's blasphemous to use anything for it's intended purpose, so forget I ever said that))
  • 1 - 56 quart plastic storage container (you do not need the lid)
  • 3" exterior wood screws (preferably star head, because they're just so much better in every possible way)
  • 1 5/8" exterior wood screws (you will probably have to settle with the inferior phillips head models for these, most stores don't carry them with star heads)
  • 4 small nails

In addition, you will need a drill, jigsaw, circular saw (you can get away with just a jigsaw), 1" and 1 3/8" auger bits, zip ties (or a few feet of galvanized steel wire), pliers, wire cutters, a hammer, 1/4" and 1/16" drill bits, and phillips and star head screwdriver bits, scissors, and a utility knife.


Just a few safety notes and procedural tips before we get started so that nobody kills themselves. READ THEM!

First, please note that I will not be walking you through how to "cut a 16" length of 2x4." The cutting process is implied when I list what you'll need at the beginning of each step. Also, it is your choice whether to do all the cutting at once before you begin, or to cut the pieces as you need them.

On that note, measure twice, cut once.

The images have many helpful tips in their notes.

Drill pilot holes. Yes, you can get self-drilling screws, but pilot holes are better.

When using a circular saw, remember to support both sides of the board you are cutting so that the wood doesn't pinch the saw blade and cause kickback. I still have a scar on my left hand from when I first used a circular saw and failed to do this. If I had not been extremely lucky, I would have gotten a lot worse than an inch long gash across the back of my hand (the saw bounced on the wood and flew over my hand, carving a slice only 1/4 inch deep instead of cutting half my hand off).

If you use galvanized steel wire instead of zip ties to attach things inside the cooler, put a bit of duct tape or something over the cut ends of the wires after you twist them together. They are extremely sharp after you cut them (which I found out the hard way, several times, which is why I replaced the wire with zip ties when I took the cooler apart and rebuilt it to show you guys how to put it together).

The cord to the utility pump is waterproof and can be submerged, the cord to the fan can not! Also, please note that while the utility pump's cord is insulated, the prongs are not insulated! I know, it may seem obvious to you, but a reminder doesn't hurt .

Step 3: Build the Base

We're going to start off by building a base for the cooler to sit on. Start by taking the 23" 2x4 and 2 16" 2x4s and screw them together with 3" screws as seen in the first image. Use 2 screws for each joint. Once you've done that, place the 16" by 26" piece of plywood on top of the "C" shape you just made. Secure it with 3 evenly spaced 1 5/8 inch screws on each of the short sides, and 4 screws on the long side. You should now have the base shown in the third image.

Step 4: Add the Sides

Now take your 16" by 24" pieces of plywood and cut a 1 1/2" by 3 1/2" rectangular chunk out of one corner of each. Once you've done that, attach the sides as shown in the second image. Put 6 screws in using a zigzag pattern as shown in the third image to avoid splitting the wood. You should now have the sides attached as shown in the fourth image.

Step 5: Cut a Fan Hole

Now you need to cut a hole in the face of the cooler (which is not attached yet) to insert your fan into. First, take your fan and position it so that it is centered horizontally and the edge of the fan is 2" below the top of the base (the 26" sides will be horizontal). Now trace the edge of your fan with a pencil. Now, use a 1" auger bit to bore a hole somewhere inside the area which you need to cut out. Using a jigsaw, start cutting from the hole you just drilled, first cutting out to the edge of the fan hole, then cutting along the edge all the way around. Make sure to support the section being cut once you get down to the last few inches, but make sure your supporting arm is not in the way of the saw. That would be bad.

Step 6: Attach the Face

Now it's time for us to attach the piece we just made to the front of the cooler. The front is the side with the 23" 2x4 (the back of the "C" shape we made in the first step). First, lay the cooler down so the front end is facing up. Then, screw in 8 of the 1 5/8" screws in a zigzag pattern (like when we were attaching the sides) along the bottom of the face as shown in the first image. Now that you've done that, turn the cooler onto one of it's sides, and place one of the 3 1/2" 2x4s under the plywood in the top front corner (top front when it's standing up, not laying down). Now put 2 of the 1 5/8" screws through the plywood into the 2x4 underneath, as shown in the second image. Now, turn the cooler so that the front is facing up again, and put two screws through the top corner of the plywood and into the 2x4 block as shown in image 4. You may need to put some weight on the face to keep it lined up while you put in the screws. Once you've got one side done, repeat this process with the other side.

Step 7: Add a PVC Pipe Shelf

Now we need to make a little shelf to hold up the PVC pipes which will circulate the water. To do this, use 3" screws to attach a horizontal board on each side so that the top of each board is 1 1/2" below the top of the cooler. Attaching these boards is a bit annoying because you have to hold them in place with one hand and screw in the screws with the other. All I can say is that pilot holes are your friends. Once you have the shelves attached, turn your cooler so that the front is facing away from you, and drill a hole through the shelf on the right side using a 1 3/8" auger bit. You want the center of the hole to be 2 1/2" in from the back and 1 1/2" in from the side of the shelf (not including the 3/8" plywood).

Step 8: Add Spacers

This step is really simple. Set your cooler upright and stand behind it. Now tip it over to the left. Now take the remaining pair of 3 1/2" 2x4s, and use 3" screws to attach them to the edge next to the base as seen in the image. These will ensure that your water basin is positioned properly to avoid leaks.

Step 9: Build PVC Pipe Assembly

Next you want to build this thing out of your PVC pieces. Cut everything first (measure carefully) and press it together tightly, and it will all fit perfectly. After you have cemented together the pipes, starting 2" in from each of the 90 degree elbows, drill a 1/16" hole every 1/2" in the 3 long parallel sections of pipe. Make sure to leave 2" without holes at the ends though, or it will leak everywhere. If you don't understand what I mean, put the pipe assembly into the swamp cooler (next step) and look at what parts of the pipe are directly over the shelves. You do not want to drill any holes which will spray water onto the shelves.

Step 10: Insert PVC Pipe Assembly Into Frame

This is another very straightforward step: Insert the PVC assembly into the frame. Start by putting the end with the male threaded adapter through the hole you drilled in one of the shelves. You may have to cut off a bit of the adapter with your utility knife, because many of them have annoying nubs on the sides which will not fit through the hole. Cutting these off will not break the adapter. After you have inserted (read: forced) the pipe through the hole, you will notice that the shelves support most of the pipes. However, where the vertical overflow pipe leads back down to the bottom of the cooler, we need to give it a bit of extra support. Put a 1 5/8" screw into the shelf next to the overflow pipe, but leave about 3/8" sticking up. Now put a zip tie around it to hold the overflow pipe in place as shown in the third image.

Step 11: Insert the Fan

Now we need to add a fan to our cooler. To do this, first take a look at your fan. If it has a base, figure out how to remove it. Simply smashing the base to pieces with a hammer until it can be brute-forced off is fine here (just don't break the actual fan), we don't need the base for anything, so remove it by any means necessary. I was lucky in that I just had to smash a couple of aesthetic plastic covers and unscrew the screws underneath. Now, drill holes at 4 evenly spaced points along the edge of your fan as shown in images two and three. Once you've done that, put one of your shorter screws in each hole closest to the back of your fan, leaving about 3/4" sticking out, as shown in the fourth image. Now, insert your fan from the back of the cooler face so that it sticks through the hole you cut for it. Hold the fan in place while you insert screws into the remaining four holes on the outside of the cooler face, locking your fan into place as seen in images 5 and 6.

Step 12: Drill Another Hole

Drill a hole in one side of your cooler for the power cords to come out of. Use a 1" auger bit. It doesn't really matter where you put the hole.

Step 13: Cut Out Pads

Use a scissors to cut the air filter into 2 15 1/2" by 15" pads and 1 15 1/2" by 13 1/2" pad.

Step 14: Make Pad Holders

Use your galvanized steel welded wire fence to make holders for the pads you just cut out by cutting out two sections of fence that measure 15" by 28" and one section which measures 13 1/2" by 28". Fold them in half and cut some of the wires so that you can bend them inward and stick them into the cooler pads. Then take your cooler pads and put them into the frames as seen in images 3 and 4. Secure them with zip ties as seen in image 5.

Step 15: Add Airflow Restriction Boards

These boards force more air through the filters by blocking the path around them. The angled ends are to direct any water that gets on them back into the basin instead of onto your floor.

Cut two 13" 2x4s with 45 degree angled ends as shown in image 1. Attach them to the sides of the cooler directly below the pipe closest to the front as shown in images 2 and 3. Use two 3" screws for each. After you have attached them, drill a 1/4" hole in the left board and secure the overflow pipe to it using a zip tie as shown in image 3.

Step 16: Add Cooler Pads

Now use zip ties to secure the cooler pads to the pipes as shown in the images. Make sure to center the pads so that they are directly below the rows of holes in the undersides of the pipes. This step is better explained visually, so I'm not going to provide a lengthy written commentary to compliment the images.

Step 17: Prepare the Water Basin

Take your storage bin and use your jigsaw to cut all but the bottom 6 1/2" off. Now slide the basin under the cooler pads. You may want to sand the edge (or run your utility knife around it) when you're finished cutting so as to remove any sharp or jagged pieces of plastic.

Step 18: Add the Pump Assembly

First, place your utility pump in the corner of your basin underneath the end of the PVC pipe which has a male threaded adapter on it. Thread the pump cord under the pads and through the hole you drilled for the fan cord. After you thread the cord through the hole, drill a 1/4" hole in the front edge of the cooler, right next to the cord hole. Now take a zip tie and tightly attach the cord to the side of the cooler. Make sure that there is enough extra cord inside the cooler for the cord to angle upwards toward the hole. You need to do this because otherwise, the cord can catch water and guide a stream of water down the cord, out the hole, and all over your floor. You don't want that. Now, measure the distance from the threaded adapter on the pump to the end of the PVC pipe. Now cut a piece of 1/2" poly irrigation tubing that is about 1 1/2" shorter than that distance. Now, push the compression fit adapters onto either end of the poly tubing to make the assembly shown in image 1. Now look at the end of the adapter. You should see a rubber washer with a fine screen covering the center. Take your pliers and use them to pull out the washer. Now use your pliers to rip the screen out of the center of the washer. Now put the washer back into the adapter without the screen. Repeat for the other adapter. The screen greatly restricts the water flow through the pipe, which will cause your pump motor to burn out. After you've done that, drill a 1/16" hole in the poly tubing about 2" above the end of one of the adapters. This will prevent the pump from air locking. If you don't know what that is, don't worry about it, because now it won't happen (it says what it is in the pump instructions if you're curious). Now screw the adapter closest to the hole you just drilled onto the pump and the other adapter onto the PVC pipe. Make sure the anti-airlock hole is facing inward a bit so that it doesn't spray water onto the floor. Almost done!

Step 19: Add the Top

Now, take your pair of 1x8s and attach them to the top of the cooler as shown. The rear one should be attached with 1 5/8" screws, while the front one should be attached by drilling 1/4" holes in it and hammering 4 small nails through the holes, which will make a removable cover through which you can adjust the fan.

Step 20: Finished!

Yay! We're done!

"Now how do I use it...?"

To use your swamp cooler, set it in front of an open window, fill the basin with 5" of water, plug it in, and turn on the fan. In order to circulate cooled air throughout your house, open a few windows in other parts of your house. The swamp cooler will suck air in through the window it is in front of, and push air out of the other open windows in the house, circulating cool air around in the process.

Swamp coolers, unlike conventional AC units, operate on an open system, which means that in order for them to work, you must give them a constant supply of hot air which they can use to evaporate water. This is why we place the cooler in front of an open window and leave other windows open.

Never let the water level in your cooler get below 2" or you risk having your pump overheat. Check the water level before each time you turn it on.

Dump the water every few weeks (or as needed) and clean the pads every few months (again, or as needed) to avoid having your swamp cooler start to smell like a swamp thing.

Now go have fun in your new air-conditioned house!

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