Greener Dryer Better: LCA of Hand Dryers vs. Paper Towels

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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