The Hand Drying Dilemma

Hand Dryer vs. Paper Towels

By: Edge Environment

You just arrived at your favourite restaurant in town after work. You noticed a bit of marker on your hands from a brainstorming session you carried out at the end of the workday (the one where you swore you nearly solved this whole climate crisis) and dash to the bathroom to wash up. Your environmentally conscious efforts have programmed you to use the most efficient amount of soap and water and now its time to dry when suddenly you’re faced with another environmental conundrum. For some strange reason the restaurant has given you two options for drying your hands: the conventional hand dryer and the disposable paper towel. Which one do you choose? Is the coal-burning electricity of the conventional hand dryer more harmful than the tree-cutting disposable paper towel? Let’s find out.

As a Life Cycle practitioner, I often find my friends come up to me asking difficult questions regarding environmental decision making in their daily lives: bus vs. train, paper vs. plastic, recyclable vs. re-usable; the list goes on and on. A quick and easy answer would be best but most situations unfortunately aren’t that clear. One of my favourites examples of this is the hand-drying dilemma; the conventional hand dryer vs. the disposable paper towel. In a complicated riddle like this, the only way to really understand the best option for the environment is to go back to life cycle assessment.

Internationally, life cycle assessment (LCA) is the most widely accepted method for assessing the environmental performance of a product of service over its whole life. LCA basically does what it says on the tin: assesses the entire life of a product, service, or operation from cradle to grave. LCA has been practiced for over 35 years and now a new method is being tailored specifically for Australia, the Australian ecopoint. The ecopoint is capable of capturing the full extent of an LCA while still bringing it back to a single-unit score. 100 Australian ecopoints is the equivalent of an average Australian’s annual impact across 13 environmental impact categories- so the smaller the amount of ecopoints, the better the environmental performance.

When comparing between two products, a common functional unit is defined in order to fairly compare each option. For example, in the case of the hand dryer vs. paper towel, we could use a set amount of wet hands to dry with a defined run time for the hand dryer and a number of paper towels used per dry. The study attempts to capture everything passing through the boundary is accounted for; raw materials, water and energy coming in, and all land, air and water emissions coming out. This information is called the life cycle inventory.

How to go about this…whilst my hands are dripping!

In order to compile the overwhelming amount of information involved in the life of this product, the life cycle inventory is classified and characterised into key environmental impact categories (e.g. kg of CO2 equivalent for Global Warming). In order to get everything to a common unit, these results are then normalised by the average impacts of an Australian citizen per year. Since some impact categories have a higher weight of importance than others1, (e.g. water scarcity has a higher weight of importance than photochemical smog), Australian weightings figures are applied to the results. Finally, the sum of these classified, characterised, normalised and weighted figures brings you to your single Australian ecopoint score.

I know what you’re thinking, that sure is a whole mess of technical jargon, but that’s exactly what makes the ecopoint so great! After the practitioners finish going through all the trouble to get the assessment complete, the end-user now has this simple score they can put to good use in their everyday lives.

The Goal – A decision!

Now let’s get back to the hand drying study. In this case, the goal of this assessment would be to see which hand drying option is best for the environment; the conventional hand dryer or paper towels.

The Scope

Three different drying options were considered: the conventional hand dryer, 0% recycled paper towels and 100% recycled paper towels. The common unit for comparison is to dry 260,000 pairs of wet hands, which is the equivalent of ten years of hand drying at 500 dries per week. The conventional hand dryer runs for 30 seconds per dry and 2 paper towels are used per dry for both paper towel options. Each option will be looked at from cradle to grave; from the collection of raw materials (steel, paper pulp, plastics), manufacturing of product (energy, water, packaging), operation of product (energy, paper), to the disposal at the end of life of the product (landfill, incineration), as well as every transport needed in between.

The Results – How to dry!

So let’s see how this works out for your hand-drying dilemma. The life cycle inventory was collected from an independent LCA study carried out by Quantis US and then analysed based on the Australian ecopoint method2.

The Figures below summarises the results showing that the conventional hand dryer is the clear winner, even in comparison to the 100% recycled paper towels! The detailed results show the main outlying impacts for the paper towel being resource depletion (abiotic depletion and land use) and its contribution to global warming. This is mainly due to the continuous demand for collection and production of more materials (paper towels) rather than the single product hand dryer.

Figure: Ecopoints Results Summary for Hand Drying Options

Although the 100% recycled paper towel came from a source that would have otherwise gone to the landfill, the processing energy and transport involved in manufacturing the end product was still a significant issue. LCA studies often help us challenge our environmental preconceptions, such as recycling not always end up being the best option. It’s always important to look at the entire life of the product in order to get the complete picture.

So there you have it, LCA has been able to make sense out of another complicated environmental decision. Keep in mind that the moral of the story shouldn’t necessarily be that hand dryers will always be the answer, as LCA is not only a good tool for environmental decision-making but it also is a key resource for informing product manufacturers and designers where the opportunities are to improve their materials and processes. So while we continue our ongoing environmentally conscious decision-making efforts, one day we can hopefully drive industry to reach that perfect, zero impact hand drying widget.

References: Dettling, J 2009, Comparative Environmental Life Cycle Assessment of Hand Drying Systems, Quantis US, viewed 10 February 2010,

1 Previously, it has been left to each LCA practitioner or tool developer to reach their own conclusions about the weighting of impact categories in the way they assess and score impacts. Now a set of Australian average weighting factors which reveal how Australian stakeholders subjectively judge the relative importance of different environmental impacts around Australia. The objective of this is to create a level playing field for assessing and comparing the environmental performance of products and services.

2 The Life Cycle Inventory figures for this assessment are based on a 2009 LCA study carried out Quantis US. The figures were applied to an Australian dataset provided with the SimaPro v7.1.8 software. This data mostly originates from research undertaken by Royal Melbourne Institute of Technology (RMIT) and CSIRO. Where required data are not available, Edge Environment has used data from the Ecoinvent database, which originates from the Ecoinvent Centre in Switzerland and compiles data from most European countries

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