Introducing the cool new technology that’s Frost Wash

Air-conditioning technology has progressed significantly across the years, yet there’s a critical area that doesn’t seem to be getting enough attention: unit maintenance. Consistent maintainence leads to a more efficient and longer-lasting air-conditioning unit – and this understanding guided the development of Hitachi’s Frost Wash technology.

Frost Wash is a self-cleaning technology that aims to maintain the balance between cleanliness and comfort. Over the course of its operation, dust and bacteria builds up in the heat exchanger of air-conditioning units, significantly affecting the quality of air it outputs. Frost Wash freezes water moisture that collects around the heat exchanger, trapping dust and bacteria in a thick layer of frost. This frost is later melted and flushed away by the unit, unclogging the heat exchanger and enabling fresh, clean and comfortable air.

During tests, Frost Wash also removed up to 93% of mould and bacteria from the interior of the unit – both particles that are harmful to health. Users also have two ways to activate Frost Wash: they can trigger it manually using the air-conditioning unit’s controller, or set it to Automatic mode. In Automatic mode, the unit will activate Frost Wash once it detects the absence of people in the room, ensuring users return to air that’s always cool and clean, without fail.

When it was first introduced in Japan, Frost Wash was well-received, with over 90% of owners testifying of its benefits. Following this good reception, the technology is now available throughout the world, and is a default feature in most of Hitachi’s range of premium models.

Average dust accumulation in Hitachi mini split after  9, 10 and 11 years usage without cleaning. Analyzed by FCG Research Institute,Inc.


Hitachi Mini Split, RAS-E40V2 after approximately 11 years of use


Frost Wash test report

·  Tested by Kitasato Research Center of Environmental Science with JCH South East Asia premium VX series

·  Test no. 2017_40194 : anti-bacterial & anti-mold effects when operating frost wash four times

by Hitachi Cooling & Heating
01 Jul 2019