Evaporative coolers don’t work in humid conditions, or so people tell you. But you can get them to work and blast cold air even when humidity is high indoors!
All you need to do is understand how these low cost air coolers work and use that knowledge to get more cooling ability from them even when the level of humidity rises to high levels in the room you are trying to stay cool in. This article will explain how to do that by using the simplest of tricks that you’ll probably kick yourself for not realizing after you read it!
Why is the Humidity So High?
First off, it’s pretty important to understand why the humidity in your room is rising so high as to stop the evaporative cooler from expelling cold air any more. The explanation is in the way the device works to create cold air.
It uses evaporation of moisture to create the cooling effect, just like your skin does when it perspires in the heat and a breeze feels nice and cool. The appliances have a big water tank that soaks a porous membrane through which air is passed by the fan. The air picks up the moisture and evaporation reduces the temperature rapidly.
That moist air is blasted into the room by the unit’s fan so you can enjoy a colder atmosphere. At the same time, all that cool, moist air is saturating the atmosphere in the room, artificially raising its humidity level. Eventually it will reach saturation point (100% humidity) and the evaporation process will no longer work, because the air cannot absorb any more moisture!
Cycle the Air
The way to prevent this happening is simplicity itself. All you have to do is open a window to let in dry air from outside and allow the moist air from inside to cycle out of the room.
You can open a door too. This will create a cross-draft in the room and allow moisture to escape, keeping the room’s atmosphere dry enough to allow the swamp cooler to keep creating cold air.
When told about this simple solution, many people are surprised that they should allow hot air from outside to get into the room. Won’t that make it hot in the room?
Actually, the room will stay cool because the cooler is still working and blasting out cold air, maintaining a cooler temperature than there would otherwise be in the room. This works very well and if you own a swamp cooler and were concerned it wasn’t working properly, please try this before discarding it!
Running Costs are Still Low
This is a big difference from running a portable air conditioner which needs all windows and doors to be closed to keep the coolness in and the heat out. AC still works with a window open, but because it costs so much to run and uses so much power, it would be extremely wasteful (and cost you a lot more in dollar terms) to run AC with a window open.
However, ventless evaporative air coolers cost around 1/20th of a comparable AC to run in terms of power consumption. So there is very little wastage by having a window open and in fact this is actually a necessity to ensure the unit keeps the room cool.
So now you know (if you didn’t already). You can run a swamp cooler in a humid room just by allowing air to cycle from outside to keep the moisture level low enough inside and you’ll still enjoy all the low cost benefits of this type of cooling process day after day!
In response to a reader’s comment, I’ve included the following note:
Note: This article is intended to explain how to get an evaporative cooler to produce better results indoors when the interior atmosphere’s humidity is artificially increased by running the cooler. It is not intended to describe how to make such a cooler work when the exterior atmosphere is also already very humid.
If you live in a really humid place (averaging above 60%), you cannot realistically expect a swamp cooler to work like an AC.
At best you’ll get cooler air blown out at you, but it will not cool a room or a whole house as effectively as AC. When the outdoor humidity gets over 70-80%, you’ll reach the limitation of a swamp cooler. Then AC becomes the only realistic choice to keep cool.