Modern hand dryers using jets of air are faster, quieter, and more efficient when it comes to drying hands and are a common sight in bathrooms around the world. There are two main designs used, hands-in, and hands-under. The latter are sometimes called blade style hand dryers because they use a very narrow jet of air to blow water off the user’s hands.

Many building owners prefer jet hand dryers because they are so much more efficient than conventional warm air designs. The speed of drying, coupled with the innovative design creates much less disturbance in the surrounding area and requires less energy to operate. As blade style jet hand dryers have become more popular, many users are curious about how they work and what makes them different from old fashioned designs.

Old fashioned hand dryers are slower and noiser

Hand hygiene is essential in preventing the spread of germs, and drying is a key part of the process. Old-fashioned warm air hand dryers work by evaporation. Slow moving air is blown over a heating element and onto the user’s hands. The user rubs their hands together in the stream of air, and the heat, coupled with the spreading motion causes the water to evaporate from the skin. This technology, while well-established, has drawbacks.

The first of these disadvantages is speed. The user needs to wait for the air to heat up before the drying action becomes effective, and then must keep their hands moving in the airflow to ensure that they become fully dry. It can take around 30 seconds to fully dry your hands in a warm air hand dryer.

The second disadvantage is noise. Slow moving air passing through a wide nozzle becomes very turbulent. This amplifies the noise of the fan and motor inside the hand dryer and this sound can spread into the surrounding area. A typical warm air hand dryer emits about 83dB of noise when in use, which is the equivalent of heavy traffic.
A third disadvantage is hygiene. As the hands dry, the water evaporates off the skin which can leave a residue of soap and any germs that were not rinsed away by the tap.

The combination of the heating element, long drying times and energy lost as noise means that old fashioned warm air hand dryers are much less efficient. Over the course of a year, it can cost almost three times as much to use a conventional hand dryer in place of a more modern blade style design, and this wasted energy also has an environmental impact in terms of additional CO2 from electricity generation being released into the atmosphere.

How modern blade style hand dryers work

Blade style hand dryers use a completely different approach to older designs. Rather than relying on slow evaporation, air is accelerated by the internal aerodynamics of the dryer and forced out of a narrow slot which then blows the water straight off the user’s skin.

With a hands-in dryer, like the Mitsubishi Electric Wave i01, the user points their hands down into a narrow drying area featuring a proximity sensor that turns the fans on automatically. Water is blown downwards off the skin and into a small tank that prevents it from going onto the floor where it might cause a slipping hazard.
The design of a blade style hand dryer addresses many of the key complaints about conventional models:

The smooth airflow creates far less turbulence and combines with the design of the nozzle and enclosed drying area to significantly reduce the amount of noise made – in use at full power, the Mitsubishi Electric Wave i01 emits just 57dB of sound – the equivalent of a quiet conversation.

Without needing to wait for the heater to reach operating temperature, the drying process is much faster – around 10 seconds in most cases, and the hands are left cleaner because there is no need to touch a button to start the appliance, or any residue left behind on the skin.

This combination of faster operation and less energy lost due to heat and noise means that operating costs (and environmental impact) are much lower. A blade style hand dryer used one hundred times each day will cost approximately £10 to run over the course of a year and the equivalent of 35KG of CO2 will be released from electricity generation – less than one third of the amount generated by a warm air hand dryer (108KG).

Find out more

To learn more about using the Mitsubishi Electric Wave i01 hand dryer in your next project, please contact a member of our team who will be happy to arrange a demonstration.

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