Old School Cool

Before AC/DC, or even AC, there were Swamp Coolers and we all loved them

I grew up in Oklahoma where, in the 60’s at least, central air conditioning or even window air conditioners were still not common. Movie theaters, the newer hotels, retail stores and restaurants all took pride in their AC or “refrigerated air” and touted it on their signage.But it was expensive to buy and sometimes more expensive to install effectively, so nearly every home had what was called a swamp cooler. They were a box the size of a washing machine, hanging on the side of the house, poking in through a window, like a window AC unit today. They were cubical in shape with the bottom few inches being the water tray which stayed full my means of a garden hose connected to a float, like a toilet tank float.

An electric pump would pump water to the top of the unit through tubing with holes in its length that dripped water down into vertical Excelsior media pads, if you want to Google what that is. These pads were about three inches thick and loosely packed so air could flow freely through them. The Excelsior pads occupied the three outer sides of the cube, with metal louvered panels covering them.

A “squirrel cage” blower, like you probably have in your home’s central air conditioner, pulled outside air through the three wet pads where the trickling water evaporated and cooled the air. The cool air was then blown into the house though a louvered plastic grilll similar to a traditional window air conditioner. You could swivel them to direct the air flow.

They are called swamp coolers because, if the unit is turned off for a period of time, several hours or a day, when you turn it back on, it blows out a mildly swampy smell which soon dissipates as the water gets moving. It is the water standing in the water tray I think that gets a bit stagnant. I believe there was some kind of additive you could put in the water tray to minimize that swampy smell, probably peroxide or chlorine tablets, but most folks just ignored it because they smelled fine once they got running.

Surprisingly, I suppose, there wasn’t much of an issue with excess humidity in the house or mold or mustiness that I recall.

In those days most cars also did not yet have expensive air conditioning. So they also had car versions of swamp coolers that hung on the edge of the driver’s or passenger’s side window glass. You’d hang it on the outside of the glass and roll up the window to hold it in place. They were about the size of a rolled up thick yoga mat.

They were cylindrical and mounted horizontally, with an air scoop opening in the end(s). A long, narrow grill inside had little directional louvers to direct the air flow to all corners of the car and a metal ball chain hanging down.

Driving down the road, outside air would be jammed in from the front, through a wet foam rubber pad which evaporated the water, cooling the air as it entered the car. You’d occasionally have to pull the chain to rotate the media pads out of the grill, down into the water tray at the bottom of the unit. When you released the chain, the wet pad would spring back into place in front of the interior grill where it would resume cooling. After a couple of hours, all the water in the tank would be used up and it would quit cooling altogether. So you’d stop and add more water to the tank.

If you were crossing the desert, it would not be uncommon to see a car with one or two canvas water bags tied to the front of the car. These bags seeped a little bit of water so the canvas was always wet. As you drove, the air flow evaporated the water on the outside of the bag and cooled the water inside the bag. Great for a cool drink in the Arizona sun.

By today’s standards, these evaporative coolers are low-tech but they worked well in that environment and were partly the reason why it took a few decades for traditional air conditioning (which cools and DE-humidifies the air) to catch on. Also evaporative coolers can cool a space for pennies on the dollar compared to the operating cost of traditional AC. In hot, dry climates a swamp cooler can give traditional AC a run for the money.

Despite the wonderful air conditioning that most of us cherish today, swamp coolers never quite went away. In fact, several companies are making modern versions that can be used stationary, portable or specialized for indoor, outdoor or combined use. There are even small units that use an ultrasonic puck to turn the water into a cool mist which a fan blows out. Certainly no NFL team would be caught dead without misting fans behind their bench during a warm weather game.

What goes around comes around and there is nothing new under the sun, not even ways to beat back that hot sun. Even ancient middle eastern peoples had ways to catch high currents of air, compress it into slender towers that pushed the cooler air down to surface level and into homes where it made quite a difference, without evaporating water.

You can find several websites and You Tubes about DIY evaporative coolers, cooling fans and misting setups for patio, pool or festivals. Something to think about the next time you’re looking for a fun project.

So, be cool everybody, each in your own way.