On hot summer nights in the early 1900s, people would often sleep on screened-in sleeping porches. Electric fans would pull the outside night air through damp sheets hung to cool the room. That concept, after being refined, became the evaporative cooler (also known as a swamp cooler, desert cooler and wet air cooler) and has been in use for more than 100 years. Although not as popular as air conditioning systems today, millions of Americans still rely on evaporative coolers to reduce household temperatures by as much as 30 degrees.

Is Soft Water OK for a Swamp Cooler?

In areas of the country where swamp coolers are fairly popular (namely dry, desert areas), water hardness is typically quite high –which means many people also own and use a water softener in the home.

We’re occasionally asked if it’s “OK to operate a swamp cooler with softened water?” So let’s review water softener basics for a moment. First of all, during ion exchange water softening process, calcium and magnesium (minerals that commonly make water “hard”) are replaced by sodium to make water “soft”. The water has gone from hard to soft, but there is now some salt in the water. So a water softener trades sodium for calcium and magnesium, you have not changed the total amount of mineral matter going to the swamp cooler, but have exchanged it to a form that may be a bit more soluble.

Mineral Buildup on a Swamp Cooler

An evaporative cooler works by evaporating water in the air stream. If all of the water evaporates, the “stuff” in the water (minerals—calcium, magnesium, sodium) will be left behind. This means that evaporative coolers operating on hard water can leave behind calcium scale build up both in and around the air cooler. And evaporative coolers operating on soft water can leave a powdery white residue—sodium. Spraying down or cleaning an evaporative cooler on a regular basis is recommended.

Advantages of Operating an Evaporative Cooler with Soft Water

While operating a “swamp” cooler on softened water isn’t entirely maintenance free, here are some definite advantages to operating with soft rather than hard water:

§ Overall cleaner water circulating through your system.

§ Soft water is better for the cooler’s pump.

§ Reduces the unit’s service and maintenance needs.

§ Reduces problems with biofilm and algae.

Reduces scale buildup which can extend the life of your cooler. (Over time, the water system on a TurboKOOL can begin to get clogged by mineral deposits and other matter in the water. This is especially true when operating on hard water).