How Does a Mist Fan Work?: The “Cool” Science Behind Misting Fans

Do you get tired of being forced to stay indoors during the hot summer days? The need to stay near an air conditioner during summertime can make you feel like a prisoner in your own home, with all the windows and doors tightly closed.

Similarly, if you manage a warehouse or garage, your workers may run the risk of heat exhaustion or heat stroke simply by doing their jobs during summer weather. The United Steel Workers has published guidelines for employers, pointing out the health and safety hazards of excessively hot workplaces.

But how exactly do portable misting fans work to keep us cool under some of Summer’s harshest conditions? In this post we breakdown the science of how mist fans work and all their benefits.

Mist systems come in various configurations, but portable fans offer the greatest versatility. These appliances combine a powerful blower fan with a high-pressure water pump. The water is blown through misting nozzles or a centrifugal misting system, producing a fog of water droplets so fine they can barely be seen. This fog is so fine that your skin and clothing won’t feel wet; instead, you’ll simply experience a fresh coolness. You need a water source for your misting fan. The NewAir fans have a connector for your garden hose, while the Luma Comfort models include a built-in water tank that you fill ahead of time. These closed water tanks allow your fan to be used indoors with no risk of leakage. When you use this type of misting fan indoors, you are not activating the water function — it just becomes a regular electric fan like any other.

The science of thermodynamics identifies three ways in which your body can lose heat, or cool off: conduction, evaporation and convection. Misting fans make use of all of three methods.

Portable misting systems cool the air through evaporation in the same way. As the fine mist shoots out from the fan, some of it simply disappears. The mist that disappears has evaporated. Since this transformation requires heat, the molecules pull the heat they need from the air around them, leaving the air cooler. Furthermore, the smaller the water drop, the faster it will evaporate, because more of its molecules are on the surface. The ultra-fine fog produced by a misting fan evaporates rapidly, maximizing the effectiveness of the process.

Evaporative cooling is most effective in less humid environments, such as the western part of the United States. If you live in a city like Phoenix, you know how dry the air feels on a summer day. If water spills, it evaporates almost instantly, because the hot, dry air can hold so much water. The drier and hotter your air, the more efficiently you can cool off by harnessing the power of evaporation. If you live in the east, however, your summer days typically have high humidity. An air conditioning unit will give you greater comfort than a misting fan will, because everything feels damp already.

Mist is so effective at cleaning smog and contaminants from the air we breathe that China actually deploys “mist cannons” in its most polluted cities as a way of eliminating particulates and smog! You and your employees, friends and family members will all benefit from the improved air quality and cool comfort that a portable misting system offers.

While misting systems are used in outdoor settings where air conditioners aren’t appropriate, it’s still interesting to note the comparative energy efficiency of the two methods of cooling. A very compact portable air conditioner uses over 900 watts of power, while the largest misting fan we offer consumes less than 300 watts. Furthermore, one gallon of water has the cooling power of 7,776 BTUs per hour. This efficiency keeps your electric bills low, while you enjoy the luxury of cooling the outdoors without any worry about wasting energy.

If your skin is moist, it feels cool. However, if you stand in the breeze from a fan, that coolness noticeably increases. This is because in motionless air, the water molecules tend to hang around right above the place they evaporated from. This makes the air next to your skin more humid, so there’s less room for any more vapor. Wind blows away the vaporized water molecules, leaving the air near your skin drier, so there’s more room for new molecules to turn into vapor and float away.

Whether you’re at home or at work, misting fans let you move around freely and focus on what you’re doing. Using three different thermodynamic methods of cooling, these versatile tools provide outdoor comfort in the hottest weather. Now you can throw open your doors and invite friends over for pool parties and backyard barbecues. Everyone will enjoy the cooler air created by your patio misting, and they’ll want to linger on into the evening.

In commercial and industrial settings, a few portable misting fans can make an enormous difference in the morale and health of your workers. Increased humidity also results in less static electricity, while the tiny water droplets reduce particulate matter in the air. The fine mist from just one fan will lower the temperature by as much as 30 degrees F in areas up to 1,000 square feet.

Outdoor festivals, sporting events and other summertime gatherings can offer cool comfort anywhere that has a 120-volt electrical outlet. Plugs and cords on portable misting fans are waterproof for safe operation, and the fans themselves are made from stainless steel and other outdoor-compatible materials.