Which are more environmentally friendly: hand-dryers or hand-towels?

Factual Questions
1

Hi All,

I recently e-mailed the question below to Cecil, but was told he had already addressed a question about hand-dryers and was unlikely therefore to answer mine. They suggested I come to the SDMB for further assisatance, so here I am:

When drying my hands in a public bathroom, I frequently have the choice between using a hand-dryer or paper towels. Since reading a hand-dryer label proclaiming they are “environmentally friendly and reduce paper towel waste”, I have erred on the side of the dryer. But this uses no little electricity, the production of which is often detrimental to the environment. So which is less damaging for the planet?

Any thoughts?

2

I would think the hand dryer is more environmentally friendly. This site suggests that it takes about 2500 kWhr/tonne to produce paper pulp. That is about 0.05 kWhr for 20g of paper. You can run a 1KW hand dryer for 3 minutes for that amount of energy. You also avoid all the transport costs for paper towels and disposal issues etc., with the environmental issues associated with these activities.

3

Yes, but paper towels aren’t exactly the worst thing to put in a landfill - I guess they biodegrade in a matter of days. And what about the energy cost of manufacturing the dryer itself? Also, I’m not that good a judge, but I suspect I could dry my hands using less than 20g of paper. Standard printing paper is 80gsm, but I guess paper towels are roughly half that. Even using 3 sheets to dry my hands, I doubt this would come to more than a quarter of a square metre, or 10g. And it may take more than 90 seconds to dry my hands with a 1kW dryer. Anyone got firmer figures/opinions? (Not to be ungrateful for your response, IC! Thanks for getting it started).

4

Given that in my experience it takes 5-6 minutes of using a air dryer to get my hands as dry as a quick wipe with paper towels, I would go with the towels every time.

5

Unfortunately, in a landfill, this isn’t true.
Conventional landfills decompose within 30 to 50 years.

the Garbage Project began digging landfills in 1987 and exhumed 40-year-old newspapers that were both intact and readable

In my backyard composter, under fairly good conditions (water, mixing, piled to keep heat in), leaves and grass take 6-8 weeks to break down into something I want to put on my flowers. The features of a landfill that are designed to keep the garbage contained, the smell down, and the water run off contained are the opposite of what my backyard compost pile needs for fast composting.

6

Another factor is that some people (OK, Just me) when finding ONLY a electric hand dryer will chose not to wash my hands unless really needed.

7

Same here. I suppose not washing your hands is the most environmentally friendly of all, in which case the signs on the hand dryers are correct.

The one I always wondered about was the single permanent towel that just rotates around. I rarely see it, but when I do it’s always wet and disgusting. I can’t imagine that anyone likes it or that it’s at all sanitary.

8

They’re not supposed to rotate back and forth. They go from one roll to another, and then you take them off and send them to be laundered and put a new one on. And they weigh about 98,000 pounds. Gah. I hated changing those stupid things.

9

The only reason for the “ecology message” on the dryers is to give you something to read while you wait for it to warm up.
But it seldom does, so you wipe your hands dry by putting them into your pockets.
Just do this to start with, and you will save both paper and electricity.

10

Five or six minutes?? Ok, you’re exaggerating… I can shake the water off my hands and air dry them myself in only about two.

11

As a kid I would refuse to use hand-dryers (my little brother is the same) - they were just too noisy and scary-looking - so I know where you’re coming from with that. Obviously I’m over it now, or I wouldn’t be asking this question!

The general consensus seems to be that hand-dryers use more actual electricity (for the record, I dried my hands last night using a 2kW dryer in about 60 seconds), but question marks hang over paper towels’ biodegradability. However, I would have thought that newspaper paper is treated with chemicals to stop it decomposing that are not necessary in paper towels, so they may not last as long as 40 years in a landfill. Can anyone confirm/deny?

The roller towel is another interesting (? :)) angle; perhaps the manufacture/laundering of these is more environmentally friendly still (if inconvenient labour-wise…)?

Finally, yes, the best solution is not washing, but often washing is necessary/desirable. And wiping hands on trousers is next best, but not ideal if one is heading to a meeting and wearing light-coloured trousers!

And please, don’t just walk out without drying - that just leaves the door handle wet for anyone who actually bothers to dry… :slight_smile:

12
  1. wash hands
  2. hit dirty “on” button with elbow
  3. move hands under lukewarm air flow
  4. hit button again
  5. notice that hands are still not getting dry
  6. wipe hands on pants
13

I either use paper towels or just flick my hands semi-dry and then wipe on my shirt. Hate using the air-dryer things.

14

I never use the air dryers since reading that the hot blowing air spreads bathroom germs everywhere. If there are no paper towels I just stick my hands in my pockets too.

15

I couldn’t get the link to work, but that’s an interesting statistic. Electricity costs around $0.15 per kilowatt-hour, so a ton of pulp, which sells for around $650.00 costs $375.00 worth of electricity to make. Add in the cost of the wood, which runs $40.00 per ton, and takes two tons of wood to make a ton of pulp, and labor and water and chemicals and equipment, and you’ve got to wonder how the hell anyone makes money selling paper.

The fact is that it might take 2500 kilowatts to make a ton of pulp if you bought electricity to make it, but you don’t, at least not directly. It goes to that ton of wood that is lost when you make pulp. It’s not really lost, it’s dissolved into a solution of sodium hydroxide and sodium sulfide. When this solution is fired in the recovery boilers it releases 10 million BTU’s per ton of dissolved wood. This energy is what is used to make pulp.

Pulp mills are net exporters of energy. They need a connection to the grid to level out power and for starting the boilers, but produce more kilowatts than they use, and enough steam to run the process as well.

Paper mills consume energy, but an integrated mill, (paper and pulp together) is very energy efficient.

As far as the paper which makes it into the landfill, what of it? Sure, it takes up room, but is environmentally harmless, or at least as harmless as the tree it was made of. The tree takes carbon out of the air during its life. When pulped, half of that carbon goes back into the air, and the other half becomes paper. If the paper remains buried and fails to decompose, that removes carbon dioxide from the atmosphere, a good thing in today’s world.

Contrast this to the electricity in the hand dryer. It probably comes from fossil sources, sources which are not being renewed and do not uptake carbon dioxide from the environment, a net increase in CO2.

Of course, you have to consider that the paper towels require transport to the facilities in which they are used, and add in fuel costs, but it really doesn’t take much gasoline to deliver enough paper towels to last a long time.

Businesses prefer the hand blowers because they require no labor to fill and trash barrels do not need to be emptied multiple times per day. They are a labor saving device, not an environmental one. Make your decision based on that.

16

Labor-saving for janitors, maybe. But if I have a building full of people making fifty bucks an hour or whatever, I’d much rather have them spend thirty seconds drying their hands on paper towels than a minute or two drying their hands with a hand dryer.

17

What you are interested in here is a Life-Cycle Analysis*. This takes into account the energy and other resources consumed in the manufacture, transport, disposal, … every step in the life-time of the item.

So I did a google on ‘hand-dryer life-cycle analysis’ and found that the analysis linked from here puts hand-dryers as the winner. This is published by the air dryer manufactuer, however the analysis was apparently performed by an independent rersearch body.

  • ISO 14040 (1997)
18

Or even better, restrooms where there’s ONLY a hand dryer and one that doesn’t even get warm either.

Actually, that’s the restroom at the city transit center. Sink doesn’t produce warm water, and the hand dryer doesn’t produce any heat. In the winter, this is pretty bad.

19

Heat requires additional electricity to produce… so see, the city saving your tax dollars :slight_smile:

20

Your assumptions are on a good base, but many pulp and paper mills use coal, oil, and/or natural gas in their electrical production boilers. That is, there is often not enough energy in the recovery boiler to run the process. I’ve been working for two mills as a consultant for the last year, and each of them requires more than (equivalent) 50MW Net of electricity and steam, all supplied by coal. Their recovery boilers and bark boilers just don’t cut it energy-wise. Their net generation costs run about (equivalent) 3 cents/kWh, FTR.