How Does a Hand Dryer Work?

You see them in restrooms everywhere – whether it’s at a gas station, a restaurant, or the local gym. Hand dryers are universal in public washrooms and you know well enough that they are used to dry your hands after you have washed them. But have you ever stopped to wonder how a hand dryer actually works? Most traditional hand dryers used to operate in a simple manner, pushing warm air out to evaporate water from wet hands. After pushing a button to activate the hand dryer, the user would stand next to the device while it was operating, being met by a loud blast of air and noise from the machine. The pressure of the air combined with its warmth would be enough to dry the users’ hands.

But that’s the old school way of doing things! The loud, ineffective hand dryers in public restrooms of the past are a far cry from the diverse and advanced options available on the market today. Now, many high speed hand dryers utilize motion detectors and infrared technology to automatically turn on and off when someone’s hands are present. Some models of high speed dryers include an infrared light that bounces back onto a sophisticated sensor to activate the dryer’s operation completely touch-free. The sensor then triggers the hand dryer circuit by means of an electrical signal to draw power from the main supply line. Older hand dryer models use the motor to power the fan to blow air through a wider nozzle after it has passed over a heating element. This uses a lot of energy and leads to higher operating costs. New high speed dryers force air through a much narrower nozzle, relying more on force than heat to remove water droplets from users’ hands. As there is little to no energy required to provide heat with the modern hand dryers, costs are significantly lower while energy savings are pointedly higher.

Since hand dryers have to draw air in from the surrounding environment in order to blow air back out, the quality and cleanliness of the air used by the hand dryer is an important factor to consider. Many modern hand dryers come equipped with HEPA (high efficiency particulate air) filters that help make them far more hygienic than those of the past. The HEPA filters remove 99.97 percent of bacteria from the air so hands are dried using clean air versus dirty air as with older models. Although you cannot see the harmful particles in the air, they are certainly there. Advanced HEPA filters in today’s high speed dryers help to support a hygienic, sanitary restroom environment.

Now that you know how hand dryers work, we bet you’ll appreciate that quick and efficient hand drying experience even more the next time you find yourself in a public washroom!