As people look to save money on utilities, evaporative cooling, also called evaporation and swamp cooling, has gained attention. This is a system in which cold water evaporates, and the cool vapor is blown out of the unit. Because evaporation uses less power than refrigeration, which is the traditional air conditioning as you know it, people think that using evaporation will save them money. This is not always the case. In fact, refrigeration may be more cost-efficient for you.
Better Humidity Removal
If it's a particularly humid day, the refrigeration unit will pull moisture out of the air that it's cooling. The air that's returned into the room will be drier and more comfortable. If you leave that moisture in the air by using a swamp cooler, the air will feel warmer, closer, and heavier, and you'd have to buy a portable dehumidifier to remove the moisture and feel better. That means spending more money on not only the dehumidifier but also the electricity to run it.
Better Cooling in Humid Conditions and Extreme Heat
Most cooling systems have their limits, and this is especially true of residential refrigeration and swamp coolers. When it gets very, very hot and humid out, even the best refrigeration unit may struggle to cool the interior of your home more than about 20 to 25 degrees. But refrigeration has an edge as it also removes a lot of moisture, so those 20 to 25 degrees go "further" in terms of making your home feel more comfortable. The drier the air, too, the cooler it feels. Swamp coolers add humidity as the cold water evaporates, making the cooling from the unit seem not as effective.
And even if it isn't very humid, you still want to use refrigeration if it's very hot and your home doesn't have good insulation. When you are in a structure that doesn't have good insulation, you have a lot of thermal transfer. That's the transfer of heat that occurs, into or out of the house, and on a very hot day, you can have a lot of heat seeping inside. If you use a swamp cooler, you'll cool the place down somewhat, but you'll also add humidity and make the place feel warmer overall as both the added humidity and transferred heat combine.
How does that save you money? You may run a refrigeration unit less or be able to set its thermostat to a more reasonable temperature. With evaporation, you'd be running it so much and trying to lower the temperature that you could easily spend more money on the evaporative unit than you would for refrigeration.