Greener Dryer Better: LCA of Hand Dryers vs. Paper Towels
by Jenna Watson, Barcelona 
on 05.18.07
People always ask me whether paper towels or hand dryers are more efficient. I have never really truly known the answer, so I always give a questioning shrug and say, “I drip dry, but I’ll look into it.” I have finally found at least one answer to that question according to Environmental Resource Management in an independent study they carried out for AIRDRI. This streamlined LCA looks at the dryer system including manufacture and supply of the dryer (plus packaging), electricity consumption for drying hands and the dryer disposal at the end of its useful life, which for the study is 5 years. On the paper towel side they consider the manufacture, supply and disposal (at the end of their 5 year useful life) of the towel dispenser, the bin for towel disposal, bags for the bin and the paper towels (plus the packaging for all of those components). The study assumes a 30 second drying time and two-towel usage. We can see in Table 3.1 (page 11 of the condensed report) that the hand dryer system does better in all impact categories except for resource depletion. Resource depletion is limited to non-renewable resources such as coal, oil, gas and minerals. The table also includes the energy use for each system even though it is not an impact category; it is interesting to see that the dryer has the lowest energy use of all the systems studied.
From Table 3.1 it can be seen that a drier, over its life time, will result in a global warming burden of 1.6 tonnes of CO2. This is an equivalent burden to that associated with a car travelling 5 100 km. Over the same period, the use of paper towels would result in an average CO2 burden of 4.6 tonnes. This is an equivalent burden to that associated with a car travelling 14 500 km. From Table 3.1 it can be seen that a drier over its life time will result in an acidification burden of 10.2 kg of SO2. This is an equivalent burden to that associated with a car travelling 5000 km. Over the same period, the use of paper towels would result in a average burden of 13.8 kg of SO2. This is an equivalent burden to that associated with a car travelling 6700 km.”
Not surprisingly, the largest contributor to the environmental footprint of the dryer is the generation and supply of electricity. Of course if we did a sensibility analysis and looked at these results with different electricity profiles we would undoubtedly see that the impacts would lessen with the use of cleaner energy sources like wind and solar. Table 3.2 from the report shows the contribution of electricity generation/supply to impact category studied. It contributes to more than 95% of each of the categories except for resource depletion (69%).
This also provides more evidence that one of the biggest keys to more sustainable products is greener and cleaner electricity sources. Additionally, the study notes that the use of paper towels has double the global warming burden of the hand dryer. I will probably keep drip drying my hands or wiping them on my pants, but in the event that I have to choose between paper towels or a hand dryer (based on this report at least) I'll pick the blowier, greener choice of the hand dryer.
The 23-page, free-for-downloading report is worth a read. You can download it here.
Read about more energy efficient dryers here. And here with input from LCA expert Greg Norris.
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I always figure that if your hands are clean, what's wrong with wiping them on your pants? Assuming your pants are reasonably clean...
an independent study they carried out for AIRDRI
Isn't that a contradiction? If they carried it out for a client, how could it be considered independent? And why is it whenever one sees an "independent" study that's funded by some interest, it always reinforces the supposed inherent superiority of the product or service provided by that interest?
Just some things to consider.
Also, did they look at reusable towels?
I think that hand dryers are also considered more sanitary by most studies. I wonder how the high speed ones in Japan and by Dyson compare though?
another vote for pants.
pants
Is it really an "independent" study if it was carried out for a company? I am guessing the AIRDRI company paid for the study. Sounds sort of like the fox guarding the henhouse, or at least paying for an independent guard.
The thing I don't like about electric driers is it overlooks a very important hygenic function of the paper towel in the public restroom -- acting as a barrier from potentially the filtiest part of the room: the door handle.
Just think of all the people who don't wash their hands who touch that thing. This is why medical schools teach you to open the door with your paper towel before throwing it out. Otherwise you risk infecting yourself with someone else's feces who failed to properly wash their hands.
I have heard that paper towels do a better job of removing unwanted bacteria etc than hand driers...this was a while ago, so maybe it improved. However, in the right context ...the towels may be better simply because the can be used to clean other things.
I think it would be a better all around idea to bring back the reusable handkerchef.
Jenna - Pablo covered this a while ago on Ask Pablo. LINK HERE. It would have been nice to get a link!
Author's note:
Thanks for the link. Unfortunately, looking at the energy consumption and CO2 emissions of a product does not a complete life cycle view make. The point of an LCA is to look at various environmental impacts over the course of the entire life cycle, from extraction of raw materials to disposal. Calculating the energy consumption and CO2 emissions, as Pablo did, does not give a complete view of possible emissions and impacts. I don't think that the AIRDRI study is the be-all and end-all of comparing hand dryers and paper towels, but I tend to think it gives a much more complete view of emissions than Pablo's calculation.
I have a 4th solution, which may be the best and most realistic solution in many situations. Have you ever been to a public restroom at any of The Ritz-Carlton hotels in the world? Well, they do not use paper or a mechanical dryer to dry ones hands. The offer re-usable (once washed) small hand towels! Once you have dried your hands, you simply toss the soiled towel into a laundry basket type of container.
Most of us use this solution at home, so why not in a public environment? Yes, for some locations this does not make sense, for lower level restaurants and bars, you can imagine the cost to replace these due to theft. But for more established and upscale retailers, why not use small hand towels?
Might be better than you pants => chamois cloth - drys your hands quickly and very well -it drys fairly quickly - - reusable - washable - can be carried in a purse or pocket.
A hand dryer used in an airconditioned building will warm the air up. That has to be compensated for by the AC, which uses a lot of electricity.
I'm not too sure what hotel I saw it in, but there was a cloth towel dispensed in, what looked like, a normal towel dispenser, but it fed the clean and washed towel down to wipe your hands with. Then it was wound back into the dispenser where a custodian would later take it out to be washed and then refilled with a clean roll of this cloth towel. I'm not sure what the energy/environmental impacts are of this type of towel dispenser, but it seems like the most eco-friendly of 'em all.
I like to use dryers, but a big thing for me is having a paper towel to open the bathroom door with. If you're going to touch the door handle with bare, clean hands, then don't bother to wash your hands at all.
To answer this question:
!Is it really an "independent" study if it was carried out for a company? I am guessing the AIRDRI company paid for the study. Sounds sort of like the fox guarding the henhouse, or at least paying for an independent guard."
I can tell you as an LCA practitioner that completely independent studies are often carried out the request of a product manufacturer. I have always carried out LCAs of products without bias for clients. That is an LCA practitioner's moral obligation. If all practitioners do that - that's another question. But I can say that everybody I know does their studies objectively. And companies are in a bit of a bind, if they don't commission a study they will be called irresponsible, if they do commission the study they are accused of bias. Who should commission LCAs then?
Vote for "Bring back the reusable Handkerchief."
In subcontinent, papers are less used and handkerchief is an important part of dressing up.
Its considered to be good manners to carry a handerchief and using it while coughing or sneezing and yes can be even used for drying your hands.
those things are LOUD!!!!! we have one at my job and people usually skip it because its almost ear piercingly loud.
"I think that hand dryers are also considered more sanitary by most studies. I wonder how the high speed ones in Japan and by Dyson compare though?"
The Xlerator in the pic is high speed. We have them at our university and I literally use the thing for 5 seconds and my hands are plenty dry. According to the manufacturer they also use 80% less energy than traditional hand dryers.
This was a question on my final exam for an Energy + Resources course I took as an undergrad at UC Berkeley way back in 1998. Same answer though: hand dryer was the better choice. Interesting that it's appearing as newsworthy nearly ten years later.
At work, it is easy to keep your own hand towel and bring it with you to the washroom. I put a small hook under my desk where it hangs to dry. In addition to using neither the dryer or the paper, it can help open your coworkers eyes to the magnitude of their daily resource consumption and to the ease and elegance with which that can be reduced.
The study doesn't seem to take into account that putting the paper towels into land-fill must act as a carbon sink. So I suggest that the overall CO2 impact of the towels may be less than is given. Would anybody like to work out by how much?
"The study doesn't seem to take into account that putting the paper towels into land-fill must act as a carbon sink. So I suggest that the overall CO2 impact of the towels may be less than is given. Would anybody like to work out by how much?"
Don't landfills release lots of methane because of the decomposition without oxygen?
Okay so fair enough, but (and I confess freely to not scouring all available resources to gain a full understanding of this), where does coal come from? And why is burying paper all that different?
If digging up coal and burning it is bad, why isn't burying (processed) trees good?
No doubt this is hopelessly naive!
"If digging up coal and burning it is bad, why isn't burying (processed) trees good?"
The difference is that trees are useful when alive, and that the quantity of trees we'd need to safely bury (not just landfill) to sequester their carbon would need to be immense, and that would create worse side effects than that solution.
Again fair enough, but I'm not suggesting using this as a means to eliminate global warming and replenishing the coal reserves, merely to alleviate the effects of the disposal of non-recyclable paper waste in a topic that's talking about (almost) exactly that!
Incinerating the paper towels will clearly release the carbon straight into the atmosphere, which as long as we grow enough trees to replace the towels should be carbon neutral (energy use during the lifecyle is not the issue here), if land-filling it release CH4 then that's worse as the CH4 is much more noxious for our purposes.
But some of the carbon is held in the landfill so if the CH4 is captured and burnt to produce energy (and CO2 and water) then the overall impact is lowered.
The actual impact depends upon the percentage of the carbon that converts to CH4 and the proportion of that that can be retained and burnt. The energy generated (though probably small as we don't believe in perpetual motion) can also be offset against some of the CO2 usage (to avoid double counting it. I have no idea what figures would be appropriate for these variables.
The question as to "where does coal come from?" is really to illustrate the point that rotting organic matter does sequester large quantities of carbon and that burning all that is exactly what is getting us into this mess in the first place.
I don't know, let's fact it, we're all doomed. But at least I intend to die with dry hands.
What about composting paper towels?
I'm not sure the hand dryer would still be greener in that case.
And also if you have a "controled debit" towel dispenser, it is proven that there is a real consumption reduction at the source.
Finally, I personnaly use only ONE paper towel. Even if it becomes really wet at the end, it does the job!
Reusable towels also use energy and water in being cleaned, not to mention the cost of labor.
I would really like to know the comparative environmental impact between paper towels and fluffy white (reusable) hand towels, on the basis that each is used once only before being discarded to waste or conveyed to laundry to be treated with bleach, detergent, hot water, washing machine and dryer (must be dryer to keep them fluffy). I have been trying to get my golf club to change from the latter to the former on ecological grounds but I may be entirely wrong and misguided.
I liked the tip about providing your own towel and keeping it on a hook.
Don't wash at all
paper towels are better..yea yea
air dry is better
air dry is better
I thinkhand dryers are better. They do use less energy or we can use the hanckerchief style again. These two things wiil help the prevention of GW (GW is global warming). Useing paper towls kills trees thats a reason 4 GW. So we can help prevent and save the destroction of earth and people a like.
The LCA analysis didn't look at the level of bacteria that is left on the hands after using the air dryer compared to paper towels.
Then, you need to consider where the air used to dry the hands comes from? The washroom, which has an abundant source of bacteria floating in the air... the ones that you just removed from your hands when washing them! Don't forget the fact that most of the time, the air dryers don't leave the hands dry after use so they actually end up contributing to an increase in bacterial growth on the hands.
This is an interesting LCA, and certainly the facts concerning paper towel are a useful guide... but there are several aspects that need to be considered. (or point it out to me if i'm missing something).
The location of a hair dryer and the electricity that was used to make the hair dryer as well as operate the machine is immensely important. Unlike paper towel that will have the same global warming potential (GWP) regardless of where it's made or used, a hand dryer uses only electricity.
Therefore, if the dryer was made and used in Quebec (100% hydro electric generation) the GWP would be nothing more than the fabrication and disposal of the unit itself. If, however, it was made and used in Alberta, there is no doubt it would be responsible for more GHGs than it's paper towel counterpart.
Finally, even without having done any analysis, i can say for sure that using a towel made from natural fibres, and washed in cold water with a biodegradable detergent and hung dry is certainly the 'greenest' way to go. Water usage, in North America at least, has a very low GWP.
Okay, as we all know...drip dry would ofcourse be the best thing to do. I mean, is it so bad to be wet? I assume most of us shower. Anyways, I just wanted to comment about this. I am a janitor at a university and I see how wasteful everyone is. It's astonishing. I basically clean restrooms for a living and I have to say that paper towels are a huge waste. First, most people don't use just one or two...they use a whole handful. They do more than dry their hands with them...blowing noses, covering toilet seats, etc. And we use A LOT of them! In the building I work in, the custodial dept. spends $10,000 dollars a month on paper products alone! If you look at the overall footprint of it, it's disturbing. You have to take into consideration that these paper products do more than just kill forests...they have to be shipped! Every month we get a shipment...this means gas burning vehicles are all over our roads. And think about all the energy used to produce the money that we spend on all of this. I don't think this study took into consideration everything that contributes to a "foot print"...if it did, there would be even more of a difference between the two. And besides...really...humans have survived for thousands of years without having to dry their hands. We're not going to die because of wet hands.
This is a great example of how mind boggling it is to address "what is sustainable?"
go with hand dryers, no paper towels, and forget about reusable -The laundry bill alone (energy, water, and labor) is not worth it.
Doing away with the extra cost and labor of paper towels is astonishing to the bottom line. Remember the third leg of the sustainable stool? Social responsibility. If we can make the life of one or two custodians easier, I think we did the right thing.
A couple of times after our office bathroom ran out of paper towels and I was forced to drip dry, I noticed how amazingly fast they drip dried. After vigorously shaking off the excess water in the sink and rubbing my hands together to spread out what little water remained, they were dry by the time I got back to my desk. I have been a drip dry convert ever since. Zero waste, zero energy use. Why would I do anything else?
And to answer the question of how to open the bathroom door without picking up other people's kooties: pull your shirt sleeve over your hand to open the door.
What did they do 200 years back. Bacteria was there at that time also. Too much waste of productive time.