Swamp Cooler – How To Pick The Right Size To Really Cool A Room
The swamp cooler is becoming more and more popular as a cost effective way to cool or an automotive shop. They do not rely on the standard refrigeration process in order produce cooler air. A typical swamp cooler uses good old fashion evaporation to cool air in a room. This evaporation process is both energy efficient and easy on the environment. Swamp coolers have been used for decades in dry, desert climates where they work the best, but you will also see these units behind the benches of your favorite football team in those hot September months. Auto shops have also started using them as an inexpensive way to keep their shops cooler and mechanics more productive. However, there may be some confusion on how they operate and how to select the correct size swamp cooler.
The temperature of air coming out of an swamp cooler obviously depends on the temperature and the humidity of the air going in. A swamp cooler can deliver comfortable air under a wide variety of typical summertime temperature and humidity ranges.
In addition to dropping the temperature of the air, evaporative cooling offers an additional cooling benefit. The constant movement of the air created by the blower – the cooling breeze it creates, if you will – makes the occupants of a room feel 4 to 6 degrees cooler than the actual temperature. This is the same effect you feel when you turn on a ceiling fan or a simple window fan. For this reason, the “effective temperature” created by an evaporative cooler will feel 4 to 6 degrees cooler than temperatures shown on the chart.
An added benefit of evaporative cooling is that it works best in the hottest time of the day. As the temperature outside increases as the sun climbs, the humidity normally drops. In the early morning, for example, the temperature may be 70 degrees, with a relative humidity of 60 percent. By mid-afternoon, when the temperature has climbed to 90 degrees, the humidity may well have dropped to 30 percent – conditions that make the swamp cooler work more effectively.
For a swamp cooler to effectively cool, it must be the proper size for the job. A small portable unit, for example, will not adequately cool a large-sized room.
While the output of air conditioners are rated in BTUs (British Thermal Units), portable evaporative coolers are rated by CFMs (the cubic feet per minute of air that the cooler can blow into your home).
Whether it is for a single room or a whole house, there is a simple formula for determining the proper size of swamp cooler you need. Figure the cubic feet of space you want to cool, and then divide that number by two. The quotient will give you the CFM rating for the proper-sized evaporative air cooler.
For example, if you have a 1,500 square foot home with 8 foot-high ceilings:
1,500 x 8 = 12,000 cubic feet
12,000 % 2 = 6,000 CFM needed
Now you armed with the proper information to select the right swamp cooler for you. However, this formula may not always be needed or work for you. A good example is a large auto shop. The actual square footage may immense, but don’t let this discourage you from purchasing a swamp cooler. Many auto shops purchase a unit and aim it directly on the mechanic working. The mechanic still gets the benefit of the cool air from the swamp cooler, even though it is not cooling the entire shop. Another good example is a football team using one in an open stadium. They are obviously not trying to cool the entire stadium, just the players.