Which is better for the environment: using a heated hand dryer for 30 seconds, or using two disposable paper hand towels?
Sandy Henderson, Dunblane, Stirling, UK
A 鈥渋ntensity鈥� of UK electricity generation is 0.2 kilograms of CO2 per kilowatt-hour. Allowing for around 5 per cent transmission losses, this means that a 1.2-kilowatt hand dryer is responsible for 2.1 grams of CO2 when it is run for 30 seconds.
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Paper hand towels weigh around 2 grams per sheet, and paper requires about 2.9 megawatt-hours of energy per tonne in its manufacture. Assuming that this comes from standard UK electricity (which is, admittedly, quite a bold assumption), two paper towels are responsible for about 2.3 grams of CO2.
That probably isn鈥檛 the whole story, however. Other factors are the manufacture of the heater on one side and paper dispenser on the other, and the transport and distribution costs of both. On balance, it comes down to how much the dryer is used and where it gets its electricity from. For a building with low footfall and few occupants who are out for most of the day, the paper towels might well have the edge over a hand dryer.
Jay Pasachoff, Pasadena, California, US
The environmental impact is important, of course, and the electricity needed for a single hand drying could use fewer resources than the production of two paper towels.
But we must also consider the health consequences of blowing bacteria and viruses around the room, as well as the effect on hearing if you hold your hands close enough to an accelerated blower to make the resulting noise very loud.
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