Do Fans Actually Cool a Room?
A surprising number of debates rage about the question of whether or not fans make the air cooler. The fans in question are almost always air circulator fans – the type that spin a set of blades in a circle. These fans hide the blades within a cage-like housing to help keep people from putting their hands in the way. However, the same principles apply to drum fans, which enclose the blades in a grating-covered, drum-shaped housing.
The simple answer is that these types of fans do not cool a room. Instead, they make people feel cooler by speeding the evaporation of sweat, thereby transferring heat away from the body. That heat goes into the room. Even this function is slightly limited. In order for it to work, the air temperature must be below about 95 degrees. Otherwise, an air circulator fan will make people even hotter by transferring heat from the air to their bodies.
Are There Any Fans that Do Cool the Air in a Room?
There actually are fans that will cool the air in the room. These work by combining forced air with water. One of the most highly-regarded types, the evaporative cooler or swamp cooler, works by pulling air through a pad that is saturated with water. The water extracts heat from the air, and the cooled air is sent into the room. These systems are effective enough to replace air conditioning in certain environments.
Misting fans also use water to cool, but they work by spraying a fine mist into the air. This mist is then sent into the area by a fan. While they are very effective, the use of an open mist limits them to areas where the water won't be a problem. Such areas include barns, outdoor work sites, sports training areas, and similar locations. The mist makes it inappropriate for offices or other rooms with delicate items or surfaces.
Which Fans Should You Choose?
As you can see, not all cooling fans actually cool the room in which they are placed. Instead, some only cool the people who are in the path of their winds. This type can work well, but loses effectiveness if the air temperature nears body temperature. If the air is above body temperature, these fans will actually make people hotter.
Other cooling fans do work on the air in the room, rather than just the people within. These use water to pull the heat out of the air as it is distributed. Of these, swamp coolers are best for typical interior areas. This is because the water in a swamp (or evaporative) cooler is confined to a pad, rather than sent around the room.
When you choose a fan, be sure to pick the kind that will work best in the intended location. Basic fans are good for many situations, but they have their limitations. When you need to cool the room, rather than just the people inside, always pick one that includes water as part of the system. This will ensure that you'll get effective results regardless of the outdoor temperature.