Hand Drying Footprint Calculator
- The study behind the calculator
- How electric hand dryers impact the environment
- Are paper and cotton towels a "green" alternative?
- Public restroom quandary - hand dryers vs paper towels
- Are paper towels recyclable ♻️?
- How to use a paper towel?
- How to use hand drying footprint calculator
- The dark side of the hand dryers
- To dry or not to dry?
You're leaving a restroom - washing your hands, turning around and... there is an electric hand dryer in one corner and a paper dispenser on the other side. You're paralyzed, thinking intensively - what should I choose to dry my hands? Racking your brain to remind the pros and cons, you recall that paper towels are made of recycled paper, and they don't suck down electricity. Uff, great, you're safe. Reaching for the towel, you notice something that makes you stop abruptly - a small sheet of paper above a dryer thanking you for saving the trees. Where does the truth lie? Which option is greener?
Our hand drying footprint calculator will help you with that dilemma. Choose the drying option and intensity of use, and in a blink of an eye, you'll find out what is the carbon footprint of the chosen method. You'll also determine how many trees are needed to absorb such amount of carbon dioxide and how many have to be cut for a yearly demand of paper towels - or the amount of trees that are spared by choosing one of the alternatives. Also, if you're wondering if the paper towels are recyclable, scroll down, and you'll find the answer.
The study behind the calculator
We've decided to choose the comprehensive study Life Cycle Assessment of Hand Drying Systems as a basis of our hand drying footprint calculator. The research takes into account the whole process - manufacturing, transportation, dispensing, materials, and disposal of hand drying systems. Seven types of hand drying systems were compared - three types of towels and four electric hand dryers.
Global warming potential associated with drying a single pair of hands. Image from the cited report 
One can argue that the study was commissioned by the Dyson - the manufacturer of hand dryers - so it's not entirely reliable. However, it was prepared by MIT researchers, and the results agree with other studies and articles in this topic (you'll find some interesting links in the Reference section below).
How electric hand dryers impact the environment
What are the main pros and cons of drying your hands with electric hand dryers?
- The amount of CO₂ associated with hand drying is substantial for the most popular conventional heat dryers. "Traditional" dryers have the highest footprint of all hand drying methods, assuming the standard way of drying hands - the time of use of a hand dryer, amount of paper or cotton towels, etc.
- The main impact is the electricity usage, so it depends where do you live and how electricity is produced there. In the areas using electricity from coal power stations, the impact is higher than in the regions which use green energy.
- Modern dryers have significantly smaller global warming potential than cotton and paper towels.
- Hand dryers reduce the amount of rubbish ending up in the landfill.
- The materials, manufacturing, transportation, and end‐of‐life stages comprise a small fraction of the total impact.
You need to remember that hand dryers can vary significantly between each other (e.g., energy used from 1,500 to 2,400 watts), and that people's habits are different, so the electric use may vary a lot between models and locations.
Are paper and cotton towels a "green" alternative?
Not really. In the case of paper towels, the disadvantages list is much longer than the projected benefits!
- Global warming potential of a towel production is really high - 5.96 g CO₂ eq / virgin paper towel and 6.08 g CO₂ eq / recycled paper towel.
- Recycled towels are generating almost the same impact as virgin towels. It's because the manufacturing process is similar and the pulp produced from waste paper has nearly the same global warming potential as pulp produced with virgin pulp. Other study cited in the report found out that the difference is even more significant - over 30% - but surprisingly in favor of virgin towels.
- Virgin towels are produced from wood pulp, so indirectly from trees. Around 25 000 paper towels can be made from one average tree.
- Transportation is also a non-negligible part of CO₂ equivalent produced, as the dispenser must be filled quite often.
- A dispenser itself, waste bin, and bin liners must be included in paper towel assessment.
- Most of the paper towels end up in landfills. And it's not a negligible amount! In the US, 2% of total dump consists of paper towels.
- The usage of paper towels doesn't generate carbon footprint.
- In most resources, paper towels are considered more sanitary than hand dryers, so they should be used in places where hygiene is paramount, e.g. in hospitals.
- Can be composted, which is more and more common (but they can't be recycled).
- Recycled paper towels have a much lower impact on Ecosystem Quality index and on energy demand than virgin towels and standard hand dryers.
And what about cotton roll towels? The global warming potential is significantly lower than paper towels. Cotton rolls can be reused up to over 100 times before disposal, but laundering the towels has a substantial impact on the environment.
Public restroom quandary - hand dryers vs paper towels
Okay, we don't keep you in suspense anymore - in most cases, a hand dryer is a greener option.
The study, which is a source of data for our calculator, took into account different aspects and measures of environmental impact - from carbon footprint, through cumulative energy demand, to even human health. Below, you'll find an illustrative table showing which method is the winner in every category.
Rank order of environmental impact of the products. 1 = lowest impact, 7 = highest impact, table adapted from the cited study
|Product system||Global warming potential||Human health||Ecosystem quality||Cumulative energy demand||Water consumption||Land occupation|
|Cotton roll towels||4||3||6||4||1||6|
|Paper towels, virgin||5||5||7||7||5||7|
|Paper towels,100% recy.||5||5||4||5||5||5|
Are paper towels recyclable ♻️?
Unfortunately, paper towels are not recyclable. There are two main reasons:
- The paper towels are usually highly contaminated - with food waste, grease, or bodily fluids. They can't be "cleaned" during the recycling process, so they could ruin the effort of segregating an entire batch of recyclables.
- As paper towels are often made from recycled paper products, there's not much fiber left to be recycled, so it makes them difficult to recycle again - and simply not worth it.
If you feel guilty, but still need to use paper towels, reducing the amount used is a good first step. Also, some waste collection services take them with the yard waste. For those having a compost pile or a wormery: the paper towel may end their life there if it's not bleached or not too soiled.
How to use a paper towel?
It may sound like a joke, but there are high chances that you've been drying your hands in a wrong way for your whole life. Or - at least - you're wasting the natural resources from which the paper towels are made. Did you know that every year Americans use 13 billion pounds of paper towels? That's a heck a lot! Check out this hilarious TEDx talk by Joe Smith to get familiar with the numbers and the perfect paper towel technique.
And remember - shake and fold rule is the key to success!
How to use hand drying footprint calculator
Let's have a look at an example of how to use this hand drying footprint calculator. Assume we want to calculate the carbon footprint generated by Omni Calculator main office:
Choose the option - do you want to calculate your individual footprint or the impact of some public place or office? We're choosing the latter.
Select the hand drying system. We're using (unfortunately...) paper towels, recycled ones.
Enter the number of office staff. Assume it's 8.
Type in how often they're washing their hands, on average. You can leave the default value as well.
Determine the number of customers per day. We usually don't have any, so let's enter 0.
The calculator displays the result. We generate 88.8 kg of CO₂ eq per year, which means that over four trees are needed to absorb such amount.
If you know the habits of your team (or you can easily calculate how often the dispenser must be refilled), you can use the Advanced mode of the calculator to type the intensity use. If you think that the sheet of paper asking for help in saving trees helps, you can reduce the number of paper towels used to e.g. 1.
Check out different hand drying options yourself - but the wiping on pants wins every time. :)
The dark side of the hand dryers
Despite the fact that the hand dryer might be the more eco-friendly option, there is another thing that should be taken into consideration – our health. Recent research found that some dryers may spread bacteria and viruses instead of removing them.
The study, conducted by the University of Leeds, compared 3 different hand drying methods (jet air, warm air dryers and paper towels) and found that dryers may be responsible for covering nearby surfaces with bacteria. The bacteria spread from jet dryers was 27-fold higher than that for paper towels, and 4.5-fold higher when compared to warm air dryers. The authors of this study made the conclusion that air hand dryers may not be suitable for use in clinical settings. A similar study was performed by University of Westminster, where authors found an even bigger difference between those three drying methods, with jet air dryers spreading 1300 times more bacteria than paper towels.
On the other hand, another group of researchers from the UK showed that jet air dryers are superior to the warm air dryers.
Finally, an independent research team conducted a systematic review of existing literature in 2011 and suggested that, from the point of view of hygiene, paper towels are better than any electronic hand dryer.
The results of the described studies are varied and depend on the methods and methodology used. Moreover, some of them were sponsored by either paper or hand dryer manufacturers. What we should do then?
To dry or not to dry?
The most ecological and safest option health-wise is letting your hands air dry. If you have to, use paper towels, but try to reduce the amount used (Shake! Fold!).
The paper industry is the third largest contributor to global warming, and over 40% of the trash in US landfills is different form of paper. With this hand drying footprint calculator we want to encourage you to change your habits. Apply the 4Rs rule: Refuse, Reduce, Reuse, Recycle to your daily routine - not only to paper towels but also to everyday plastic use. Find out what's your flight travel carbon footprint, check how many trees you are saving by choosing a bike over a car. Little by little does the trick - let's change ourselves and try to live a greener life to save our planet!🌎
Writing this article, we used many different sources, i.a.