The Pros and Cons of a Shop Evaporative Cooler

The pros for evaporative cooling

• Thanks to a new awareness of energy efficiency, shop evaporative coolers are achieving a new popularity. Remember, swamp coolers use as much as 75 percent less electricity as air conditioning does. For hotter desert climates, the savings can be much more.
   
• Because the technology is simpler, a shop evaporative cooler costs about half as much as an air conditioner that will cool the same sized area. For perspective, a quick check of the internet in July 2001, found units capable of cooling 750 square feet that were priced as low as $275. Installation costs of swamp coolers are comparable to air conditioning units.
   
• Shop Evaporative coolers operate on 120-volt electricity, which means they don't need special high-amperage circuits like many air conditioners do. A swamp cooler can be plugged into a nearby outlet. Most air conditioners require 220 volts.
   
• Many people appreciate the fact that evaporative cooling adds moisture to the air, which helps to keep wood furniture and fabrics from drying out. The moist pads through which the outside air flows are also fairly efficient air filters, trapping some dust and pollen. Since the pads are continually wetted, trapped particles are flushed out and trapped in the bottom of the cooler.
   
• Air conditioning works best when the windows are closed, since interior air is cooled and re-circulated. Because swamp coolers cool outside air and blow it into the house, however, to work effectively they need at least one window open. The cooled outside air vents through open windows or doors, pushing out hot inside air and any smoke, odors and pollution that may be present. With evaporative cooling, a complete air change in a home occurs every one-to-three minutes. This flow of fresh air means that evaporative coolers can be operated without using the water pump to replace warm stale air with cooler nighttime air, much like a whole house fan does. That's an added benefit.
   
• Small shop evaporative coolers can be often placed in windows, much like a window air conditioner. This requires very little installation. Larger units usually require ducts to distribute the air, but these can be an existing forced air duct system in the house.
   
• For the most part, evaporative cooling doesn't require as much ductwork as air conditioning. For a newly installed system, a short duct can direct the cooled air to a central point in the house. From there, air can be directed through the various rooms by simply opening and closing doors and windows to allow the cooled air to flow.

• The main drawback of swamp coolers is that they depend on dry outside air to operate effectively. This is usually not a problem for most of California, which has a desert or Mediterranean climate. On hot, muggy days in the summer, however, swamp coolers will blow hot, humid, soggy air into the house. If the humidity stays high for several days, the moist pads that make the evaporative cooler work can begin to smell, and the musty odor can be blown into the house.

The cons for evaporative cooling

• Unfortunately for parts of the California desert and for much of the desert Southwest, July and August constitute the rainy season, when monsoon storms sweep north from Baja California. With high temperatures accompanied by high humidity, these months can be the least favorable for swamp coolers.

 

• Evaporative cooling requires water to keep pads wet - a consideration in some areas, especially in drought years. Water consumption can run from three to 15 gallons a day, depending on the size of the swamp cooler and whether or not the water is collected and pumped through the pads more than once. In some areas, discarded water from the unit can be an environmental concern.

 

•   Evaporative coolers can be hooked up to existing forced air duct systems. Because the air delivered by an evaporative system will be warmer than the air supplied by an air conditioner, however, evaporative coolers need to produce more air flow. That means the duct system may have to be larger to handle the volume of air and to effectively cool the house.