If you've decided to get some portable air conditioning units for your home so you can cool down certain rooms more than others, you've no doubt noticed the cost of the units. Portable air conditioning units, which are freestanding units that often have casters (not the type that sit fully in a window) can cost a lot of money, often running as high as $600. But another option, a portable evaporative cooler, usually costs a lot less than a portable air conditioner. Before you leap at the chance to get an evaporative cooler, understand how they work first. Sometimes they're not as well-suited to cooling your home as are portable air conditioners.
How They Work
Portable air conditioners take hot air from inside the room and cool it down by running it over a compressor inside the machine, much like a central system does. The vent is needed to send the remaining hot air outside. An evaporative cooler blows air over ice placed in a compartment -- it's a bigger, fancier version of placing a bowl of ice cubes in front of a fan. Both of these types of coolers sit inside a room, near a window; the portable air conditioner has one to two hoses that sit in a removable bracket in an open window.
The issue with evaporative coolers is that they also blow water vapor into the air. That ice melts over time, and the resulting moisture -- steam as the water evaporates in the heat -- heads out into your room. That makes the room more humid. If you live in a really dry climate, that extra humidity can be quite welcome.
But if you're in an area that already gets too humid for your tastes, the extra moisture isn't welcome. Even if the relative humidity is at a moderate level, the extra moisture prevents the room from cooling down quite as quickly. When there's extra humidity in the air, your sweat doesn't evaporate as quickly. The excess sweat and the amount of moisture in the air make the room seem closer and stuffier -- and hotter. If your sweat can't evaporate, it can't cool you down as efficiently as it would in a very dry situation.
Adding more humidity into the room isn't going to help you? In those cases, you need a plain air conditioner that will remove moisture as it cools the air. Remember that "too much humidity" is a subjective factor. Some people are more sensitive to humidity than others, so this is a very personal decision. However, in general, drier climates will be fine for evaporative coolers, but wetter climates need regular air conditioners instead.
If you try to run an evaporative cooler in a humid room, you'll only end up using more ice and more electricity as you place fan settings as high as they can go. Over time, that makes the evaporative cooler not as cost-effective. If you have more questions about whether your home would do better with an air conditioner or an evaporative cooler, contact a local air conditioning service such as Century Heating & Air Conditioning Services.