How Clothes Get Clean Without Water: The Technologies Behind Waterless Washing

1. Introduction

The technologies that make washing without a conventional water bath possible. Each approach tackles a different part of what laundry actually needs, whether that is removing stains, killing germs, taking out odours or smoothing wrinkles. Understanding these differences explains why the technology mix shifted over the years and why different companies placed different bets.

2. The Four Prevalent Technologies

The study identified four prevalent technologies, each tied to a flagship consumer product.

2.1 Steam washing

Steam washing turns water into vapour and uses it to lift stains and loosen dirt from fabric. Because the water is used in vapour form, the total quantity is far smaller than in a normal wash cycle. Steam also relaxes fibres, which helps with wrinkle removal. The best-known product in this category is the LG Styler steam clothing care system. Electrolux's Vapor Action washer, which the study describes as giving clothes a spa-like treatment, also belongs here.

2.2 Hot air washing

Hot air washing refreshes garments using heated air to remove odours and wrinkles instead of liquid water. The study describes it as removing stains and wrinkles from cloth. It is closely associated with air-wash products such as the Samsung AirWash and Electrolux Airwash. The study also notes a Whirlpool Air Wash model from 2013 to 2014 and an Electrolux eco-friendly machine that uses only air to treat a range of stained fabrics.

2.3 Ultraviolet washing

Ultraviolet washing uses UV radiation to sterilise clothes. Its strength is hygiene rather than stain removal: UV light can reduce microbes on fabric without any water. In patents it is usually a supporting feature added to steam or hot air machines rather than a stand-alone approach, which is consistent with the low share of patents focused on it.

2.4 Ozone washing

Ozone washing converts oxygen from the surrounding air into a blend of oxygen and ozone, which sanitises and deodorises clothes. Like UV, it works mainly on odour and germs. As the next sections show, ozone was the technology that the study found growing in importance after steam peaked and it became the favoured technology of universities.

2.5 Other approaches

• Polymer (plastic) beads: small beads are tumbled with the clothes. They help lift stains and also absorb water, so the wash needs far less of it. The study notes that Xeros' patented nylon-bead technology claims to save around 90% of the water and 30% of the electricity.
• Ultrasonic cleaning: high-frequency sound energy dislodges dirt. Electrolux is shown using ultrasonic cleaning for a wide range of fabrics.
• Orbit system: Electrolux's Orbit machine uses electromagnetic forces and solid-state carbon dioxide to clean clothes without wetting them at all.

3. How the Technologies Share the Patent Space

Across all analysed patents, ozone and steam take the largest shares, with hot air in the middle and UV a small niche. Steam and ozone together make up roughly three quarters of the activity.

Technology	Approx. share of patents	Best suited to
Ozone	~38%	Sanitising and deodorising
Steam	~35%	Stain loosening, refreshing, wrinkle removal
Hot air	~19%	Odour and wrinkle removal, drying
Ultraviolet	~8%	Sterilising

Source: study technology-by-assignee chart. Shares are approximate readings of the chart.

4. Who Backs Which Technology?

The assignee-by-technology analysis shows that each company has a recognisable specialism.

• LG holds the largest number of patents in hot air, steam and ultraviolet. Steam is its centrepiece (about 123 patents in the chart) followed by hot air (about 86), with only a handful in UV and ozone.
• Haier leads in ozone, with about 35 patents. It is the clear ozone specialist among the big appliance makers.
• Bosch splits its effort between ozone (about 27) and steam (about 25).
• Samsung, Electrolux and Whirlpool have smaller portfolios spread across several technologies.
• Universities focus mainly on ozone technology.

This division matters strategically. LG staked its position on steam and hot air, which are heat-based and well suited to refresh-style appliances. Haier chose the sanitising route through ozone. Bosch hedged across both.

5. What Are the Machines Meant to Do?

The study also classified patents by the job the machine performs: sterilising, removing wrinkles, removing dirt, removing stains, refreshing and removing odour. The overall split showed odour removal as the largest group (about 27%), followed by refreshing (about 25%), wrinkle removal (about 17%) and dirt removal (about 9%). In short, most waterless machines are designed to freshen and care for clothes more than to scrub heavily soiled laundry.

The company profiles reinforce this. LG machines emphasise refresh and wrinkle removal, which fits steam and hot air. Haier machines cover sterilising and odour removal, which fits ozone. Haier is also the company that spans the widest range of categories, covering sterilising, refreshing, wrinkles, odour, stains and dirt.

6. How the Technology Mix Changed Over Time

One of the most useful results of the study is the shift in technology focus between the early and later parts of the data.

Period	Steam	Ozone	Hot air
2012–2014	~20%	~18%	~12.7%
2015–2016	~7.5%	~16%	~4.5%

Source: study "Technology and Top Assignee Trends" slide.

Steam was the focus in 2012 to 2014 and then fell sharply. LG, which filed about 12% of steam publications in that period, saw this fall to about 4.5% in 2015 to 2016. Ozone, by contrast, held steady and the study reports that ozone became the focus in 2015 to 2016, while ultraviolet and hot air were also described as trending. The chart for individual years supports this picture: steam peaked at around 45 documents in 2014, while ozone reached its highest single-year level of about 63 in 2016.

Company-level charts show the same shift. LG's steam filings peaked in 2014 and then dropped, while hot air kept a steady presence. Haier's ozone filings jumped to about 11 in 2016. Bosch filed a steady stream of ozone patents from 2012 through 2016, reaching about 8 in 2016.

Why might this have happened? The study does not explain, but a reasonable reading is that steam had been heavily patented early, so later activity moved to areas that were less crowded or that addressed new needs such as sanitising. This is an interpretation rather than a finding from the data.

7. Key Takeaways

• Four core technologies drive waterless washing: steam, hot air, UV and ozone, with polymer beads, ultrasonics and Orbit as additional routes.
• Ozone (~38%) and steam (~35%) dominate patent activity; UV is a niche that mostly supports other methods.
• LG leads in steam, hot air and UV, Haier leads in ozone and universities concentrate on ozone.
• Most machines are built to refresh, deodorise and de-wrinkle rather than to deep-clean heavy stains.
• Steam peaked around 2012–2014 and ozone rose in importance afterwards.