I am not a germaphobe, but I agree that restrooms and door handles in particular should be given more attention by not only the cleaning staff, but design professionals in every discipline.
DC
Blog Post
Paper Towels vs. Efficient Hand Dryers: New Study Makes the Choice Clear
Drying your hands requires far more water than washing them, according to a surprising new manufacturer study.
Low-flow faucets and other water-saving fixtures have become a standard water-saving feature in public bathrooms. Unfortunately, it turns out that drying your hands uses a lot more water than washing them--anywhere from 18 to 70 liters (4.8 to 18.5 gallons) per hand-washing session, depending on the drying method. That's according to a life-cycle assessment (LCA) commissioned by Dyson, maker of Airblade high-speed hand dryers.
Hand-drying's worst enemy: hot air
The study, conducted by researchers at the Massachusetts Institute of Technology (MIT), looks at seven hand-drying methods commonly used in public bathrooms and designates Airblade the hand-drying method with the lowest environmental impact in all categories, with the high-speed XLerator dryer coming in second in most of the categories. Strangely, Airblade's higher-performance competitors don't make an appearance (more on this below).
The highest impact in most impact categories, based on the research parameters, comes from standard warm-air hand dryers.
Paper or power?
All electric hand dryers have the vast majority of their impact during use--primarily through energy consumption. Hence, those that consume less energy have a lower impact; the Airblade wins out over the XLerator, according to the study, because it takes less time to completely dry hands and has an electronic motor that does not waste energy on "spin-down." Presumably, any high-speed hand dryer sharing these characteristics would have similarly low impacts. Both Airblade and XLerator won hands-down over paper towels--both virgin and recycled. All the towel drying methods have the vast majority of their impact during manufacturing, which explains why recycled paper towels, which are manufactured in much the same way as virgin towels, have similar energy, global warming potential (GWP), and water use impacts but do better in terms of ecosystem health.
Towels' greater impact is due mainly to their disposability: even reusable cotton roll towels have a short life, so many thousands of towels would be manufactured and shipped during the five-year life of a typical hand dryer.
Looking at the whole life cycle
The LCA considers each method's entire life cycle, from resource acquisition to disposal, including everything from the water used to generate electricity for manufacturing and use--hence the high water consumption for all methods--to the global warming potential (GWP) of plastic trashcan liners used for throwing out paper towels. In a thorough "sensitivity analysis," it even takes into account a number of what-ifs--looking at how different the results would be if paper towels were composted instead of landfilled and what would happen if you used each cotton roll towel 130 times instead of 103.
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See membership options »These extra steps help mitigate concerns about biased assumptions, and the study results do generally make sense. BuildingGreen did a far less formal LCA of various hand-drying methods way back in 2002, when the then-pioneering XLerator came on the market, and came to much the same conclusion about paper towels vs. high-speed hand dryers.
Study covers emissions--also suffers from omissions
While the Airblade comes out looking clean (and dry) as a whistle in the study, it's important to keep in mind that LCA is an imperfect tool for assessing environmental impacts. These book-length reports look thorough and include more data--and more details about how the data came to be--than you can shake a stick at, but there can be significant omissions.
In this case, the most glaring one is that the hand dryer brands most similar to the Airblade, such as the Mitsubishi Jet Towel, were not included in the study results. We look forward to seeing equally thorough comparative LCAs from others in the industry--including manufacturers of high-speed hand dryers whose energy performance may equal or exceed that of the Airblade.
Checking the paper trail
In addition, paper towel manufacturers have argued with Dyson's LCA conclusions before. Kimberly-Clark, for example, has faulted Dyson for not taking hygiene into consideration in its research; the company distributes a brochure titled "Are 'High Speed' Dryers Really Worth the Risk?" (PDF) in which it claims that the Airblade increases bacteria on hands 42% while disposable paper towels reduce bacteria on hands 77%.
While Dyson has publicly questioned such claims, its latest LCA does not take hygiene into consideration at all--an odd oversight, given that hygiene is the primary justification for hand-washing in the first place. If your drying method makes them less clean, the environmental impacts hardly seem worth it.
Drying our hands with water and carbon
While we wait for more data that perhaps takes hygiene into account in addition to dryness, it's worth considering that even the Airblade dryer uses 18 liters of water and contributes 4 g of CO2 to the atmosphere every single time you use it. Isn't drip-drying or wiping hands on clothing an option? We'd also love to see an LCA of alcohol-based hand sanitizer added to the mix.
Meanwhile, watch for the January issue of Environmental Building News for a deep look at product transparency and how to get what you need from such reports while also taking them with a grain of salt.
Published December 7, 2011 Permalink Citation
(2011, December 7). Paper Towels vs. Efficient Hand Dryers: New Study Makes the Choice Clear. Retrieved from https://www.buildinggreen.com/blog/paper-towels-vs-efficient-hand-dryers-new-study-makes-choice-clear
Comments
Perhaps we should consider
Perhaps we should consider making restroom doors open outward? Then a person could simply push against it without using their hands (and needing a paper towel for hygiene). Is there a code reason this is typical, or just normal practice?
Hygiene
In my opinion, the whole point to washing your hands is to get them clean. There are those (such as the pizza guy on the Seinfeld Show) who leave the stalls and don't wash, touching the stall, the door handle and maybe the light switch on the way out.
There are others who barely rinse hands and also touch all sorts of places in the bathroom.
Given that most places are unlikely to install all new no-touch sinks, towel / hand dryers and automatic doors and light switches, the issue of RE-contamination is huge - especially in the food and health care industry.
Seems there is a clear argument for towels in their ability to remove more bacteria and provide protection to the hand while opening, closing and turn off other common places in the bathroom.
Hygiene
Here is a link to a study done in the UK about the cleanliness of towel- vs. forced-air-drying (they did not test liquid hand sanitizers or moist towelettes). Paper towels are much cleaner than hot air dryers, especially when you account for being able to grab the door handle with your used towel.
I believe using your hair or pants would not be very clean when compared to a fresh paper towel. I would air-dry if the door can be opened without using your hands.
air-dry, wipe through hair or
air-dry, wipe through hair or on pants, or (as I do) carry your own towel/scarf. All good ideas to eliminate paper/pwrd drying.
Most people don't do this, bu
Most people don't do this, but the most ecological and sensible solution is to simply dry your hands in your pockets or on your pants when leaving the rest room. No towels. No blowers. Maybe an experiment should be done in public rest rooms -- eliminate towels and blowers and put signs up requesting that rest room users utilitize this new, smarter way of drying hands. One thing to watch would be a potential reduction of people washing their hands.
I have carried a bandana or
I have carried a bandana or handkerchief in my back pocket for years, and while I rarely need it for a cold, it gets used all the time as a paper towel substitute or dinner napkin and for first aid and clean up, etc...It does need to be laundered, but they do air dry on a line quickly.
How electricity generation consumes water
John Q: Yes, hydropower is the biggest culprit, but it's not water running over the dam, it water that evaporates from the reservoir behind the dam. The water-energy connection is explained pretty well in this Primer from BuildingGreen: http://www.buildinggreen.com/auth/article.cfm/2010/9/29/The-Water-Energy...
hand drying
I would like someone explain how that much water is "consumed" in the production of electricity. Is it Hydro generated electric? Don't understand that as stable water levels would be flowing anyway. I imagine it must be other sources considered.
drying your hands
i usually just wave my hands around a little and finish by sort of drying them on my pants. ambient air does the rest.
I don't mind high-speed hand
I don't mind high-speed hand dryers except for the noise. It can even become annoying outside of the restrooms whether it's in an office or a public hallway. Manufacturers should work to lower the decibel level.
Wolfger, I wonder if anyone h
Wolfger, I wonder if anyone has done a study on how much hand dryers heat up buildings. There would be a lot of variables, but in a high-volume bathroom, this effect could certainly be significant.
Hygiene
I find it quite interesting that hygiene is not a consideration when comparing different hand dryers' sustainability and LCA's. Isn't the whole point of a "green" building to reduce the environmental impact of the building and to provide for the health and safety of that buildings' occupants? That's why building materials, paints, adhesives, cleaning chemicals are all required to have reduced or limited VOC's - to provide for better Indoor Air Quality that leads to a safer, more healthy environment for the buildings' occupants.
I too, would like to see studies looking at using hand sanitizers as an alternative to hand soap and water. Many of the hand sanitizer manufacturers are now suggesting that hand sanitizer dispensers be place at the exits of public restrooms.
Healthcare applicability
I work with healthcare organizations and in this setting, the need to include infection control issues is paramount. I've considered promoting air dryers in public restrooms as a waste reduction and labor savings effort (from receiving to stocking to moving bags of trash - its huge). The lca for water use is an eye opener even if it's better than paper towels. I'll officially join the drip dry crowd. If anyone has data on infection control/cleanliness issues, please let us know. Thanks.
I resolved this dilemma for
I resolved this dilemma for myself many years ago - I simply dry my hands off by running them through my hair! Working in a conditioned office environment tends to be pretty arid in general, so this approach works pretty well
(at least while I still have hair).........
@Dick Pennock, Good thought
@Dick Pennock, Good thought but I think the internal heat gains from bathroom hand dryers is a non-issues since bathrooms are required to exhaust all air anyway. Heat from the dryers would be sent directly out of the building along with odors and humidity.
effectiveness
Ryan, the study uses "a single pair of dry hands" as the underlying unit, so effectiveness is built into that. Believe it or not, there is actually a national standard defining "dryness" for pairs of hands.... (Not coincidentally, Dyson helped write the standard.) This "functional unit" for the study creates a standard of drying effectiveness and helps you decide, for example, how long you have to hold your hands under a dryer or how many paper towels you have to use for the purposes of the study. The high-speed dryers are certainly more effective and efficient than the old hot-air dinosaurs, which is why they use less energy. Brand names aside, the real takeaway from this is that if you really must dry your hands, go for the high-speed dryer. It has the lowest impact.
I think something that is not
I think something that is not really discussed here is the ineffectiveness of many hot air hand dryers. The Dyson Air Blade seems to work pretty effectively, but if I see any other type hanging on the wall, I usually bypass the drying part altogether. Is drying your hands really necessary to ensure cleanliness?
To be complete, the study
To be complete, the study should compare all the different ways we can use to wash/dry our hands.
What about water-less hand sanitizers and moist towelettes?
I often use the latter, and would love to know the environmental impact.
air vs. paper
Interesting article and it certainly helps my understanding.
My comment is on the talking air-driers cartoon. If my mother ever heard me say "blow me" she would have emptied the non- bio-degradable soap dispenser contents into my mouth.
My, how things have changed...........
Paper vs. Hand dryers
My wife's biggest complaint about the absence of paper towels is that she has nothing to use to protect her hand when opening the door to exit the restroom.
Actually, in Japan they
Actually, in Japan they already do - or did about 10 years ago. Small, square hand towels that fit in a bag or pocket, and come in a variety of styles and patterns are on sale everywhere - so most public restrooms do not provide either hand dryers or paper towels. But who knows, by now they may be introducing hand dryers as a more 'modern' convenience....
Why bother drying hands at
Why bother drying hands at all? The water will evaporate naturally in less than a minute anyway. I haven't dried mine in the last five years or so and have never had chapped hands.
One other consideration for t
One other consideration for the electric dryers is the heat they generate which may have to be removed via air conditioning (more electricity) in hot climates.
Maybe everyone in the future will carry their own hand towels?
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