Which is More Eco-Friendly - Air Dryers or Paper Towels?

This post first appeared in our weekly Make Waves Mondays email series on March 11, 2024.

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Okay so I have good news and bad news about this week’s blog, friend.

The bad news is, while I thought this week’s topic would be a pretty simple one, I should have known that just like nearly everything else in the world of sustainability, the answer is pretty much a solid, “Well…it depends.”

The good news is, even though the answer may be “it depends,” I’m not gonna leave you hanging at the end asking, “What the dang heck am I supposed to do then, Krystina???”

Pinky promise.

(Pro-tip: You might wanna listen to this one!)

The backstory:

Yesterday afternoon I was scrolling through my list of potential blog topics, and saw “Drying hands with paper towels vs air dryer,” which I’d added to the list well over a year ago.

For some unknown reason, I thought to myself, “That shouldn’t be too complicated! I’m sure there are plenty of studies that give a clear answer to that!”

Oh how wrong I was, friend... 

How wrong I was…

So today I sit down at my desk and start the research process. 

And at first glance, there are TONS of studies on the topic, but digging deeper into them, there are several that aren’t peer-reviewed, some that were funded by Dyson, and all of them use different assumptions in their calculations.

Of course.

BUT the more complicated it got, the more intrigued I became. #DataNerd

So now that I’m sitting here writing it all out, I’ve decided on one very important thing: to keep things as simple as possible.

I’m not going to bore you with a whole academic literature review. 

You’re welcome.

Instead, I’m gonna get straight to the highlights, and of course leave links to all of the studies I used as sources.

And at the end, please let me know what you think! The more feedback I get from each week’s post, the better I know what you want more of or less of!

Which is more sustainable for drying your hands: paper towels or air dryers?

So on the whole, the general consensus is that air dryers are the more sustainable option for drying your hands.

Paper towels are obviously made from trees, which must be cut down and go through a long process of becoming paper towels, they have to be transported, and then after they’re used they typically either go to landfill or incinerator.

On the other hand, air dryers produce basically zero waste when they’re used, and once they’ve been produced, they continue to do their job of drying hands for many years.

But when we look a little closer, there are so many factors that influence just how sustainable each of these options are.

100% Recycled Paper Towels vs. Virgin Paper Towels

Even though air dryers are typically the more sustainable option, things get a little complicated when we compare 100% recycled paper towels to virgin paper towels.

According to a 2011 study from MIT, the Cumulative Energy Demand (CED) for recycled paper towels is about a third of that for virgin paper towels, and the Land Occupation is about 10x less, too.

Cumulative energy demand (CED) includes all direct and indirect energy consumption associated with a material’s life cycle - including extraction, manufacturing, and disposal of both raw and auxiliary materials.

However, nearly every other aspect of this comparison is equal.

Of the four studies I reviewed today, only one specified whether their data was based on recycled or virgin paper towels, and only the 2011 study compared the two at all, so it’s difficult to make any meaningful conclusions about recycled vs. virgin paper towels in comparison to air dryers.

Ultimately, we can pretty confidently say that 100% recycled paper towels are the more sustainable option than virgin paper towels, but that’s not the question at hand…

Type of Air Dryer

As you already know, there isn’t just one type of hand dryer.

There are the ones I’d casually refer to as “the cheap dryers” - you know, the ones that basically feel like a light breeze on a cold day. Cold air, zero air pressure, hardly even worth it…you know the type.

Then there are the ones that you stick your hands into and an aviation-worthy gust of air dries your hands in about 2.4 seconds.

And so many in between.

All of this variation in design makes any 1:1 comparisons nearly impossible.

One study from 2021 compared the impact of replacing already-existing paper towel dispensers with airblade-style hand dryers (the ones you stick your hands in) on a university campus in Italy, and ultimately found that installing airblade dryers was more sustainable than paper towels as long as the bathroom was used, on average, more than 50-60 times per day.

But again, this is the impact of replacing already-installed paper towel dispensers with hand dryers, not exactly an exact correlation.

Another study from 2015 compared a “hands-under type warm air hand dryer, rated at 1800 watts” with 100% recycled paper towels, and found that the air dryer was more sustainable than paper towels when it came to global warming potential, human health, and ecosystem quality, but was inferior to paper towels in terms of resource use.

Then I found a 2013 study that compared three different types of air dryers (hands-under dryers, high-speed hands-under dryers, and high-speed hands-in dryers (aka airblade-style dryers)), cotton towels, and virgin paper towels. 

This study ultimately found that the “use phase” for air dryers (aka when the dryers are actively being used to dry hands) was the biggest driver of sustainability, and varied depending on whether they were used as intended (completely drying hands) or used for less time than actually needed to completely dry hands.

But if we assume that you’re drying your hands completely, according to this study, the high-speed hands-in dryers are more sustainable than the hands-under dryers in nearly every case, and more sustainable than the high-speed hands-under dryers in most cases, and the 2011 study found the same.

Number of Paper Towels Used and Time to Dry

Okay so this one seems so obvious when I’m writing it out, but it was super interesting to actually see it laid out in two different studies.

Obviously, the sustainability of paper towels is going to fluctuate based on the number of paper towels you use, and the sustainability of air dryers is going to fluctuate based on how long you use it.

The 2011 study found that for both virgin and recycled paper towels, the global warming potential was just under 8g of carbon dioxide equivalent for each towel used. 

So essentially, using one towel instead of two cuts the impact in half.

Similarly, the longer you use an air dryer, the more energy it takes.

It’s super interesting to look at these comparisons side-by-side, because it really starts to demonstrate the complexities in these kinds of studies.

Both the 2011 and the 2015 study made these “use intensity” comparisons.

Since the 2015 study was a bit more generic, it’s a little more difficult to see correlations, but interestingly, they found that the global warming potential of using one 100% recycled paper towel was still higher than using a hands-under warm air dryer for 45 seconds (or what they defined as “high use”), but that wasn’t the case for all of the impact categories they studied.

The 2011 study, since it compared different types of air dryers and paper towels, showed a bit more detail.

For all “use intensities,” the airblade-style, hands-in dryers had a lower global warming potential than both recycled and virgin paper towels, but standard hands-under dryers had a higher global warming potential than both types of paper towels.

(Basically, airblade dryers are better than paper towels are better than standard dryers.)

But looking a little closer, the study also found that using one paper towel was slightly better than using a high-speed hands-under dryer for 20-25 seconds, but if the dryer was only used for 10 seconds, it was a bit more sustainable to do that.

So many freaking variables. 

And honestly, this is where my brain started to hurt.

But are you still with me?? ‘Cause it’s about to get interesting. 😄

Energy Grid Mix

This part of the equation was where I first started to realize the answer to my question was always going to be “it depends.”

I started with the 2015 study, which was the one comparing the hands-under warm air hand dryer with 100% recycled paper towels.

Throughout the entirety of the study, in nearly every aspect, the air dryer was coming out on top compared to the recycled paper towels.

But then, the Ontario-based researchers decided that it would be fun to compare Ontario’s energy grid with the United States’... 

Oof.

According to the study, “The US supply grid relies mainly on coal as a source fuel (~50%) with natural gas and nuclear power following as the other important sources (~20% each). This is in contrast to the 2012 scenario in Ontario where the contribution of coal as a source fuel was <3%.”

So now, suddenly, where before the air dryers were clearly coming out on top with only 3.6g of carbon dioxide equivalent, in the US that number jumps up to 12.9g (!!!).

A whole 259% increase.

All of a sudden, the paper towels are the better choice in 3 of the 4 impact categories.

And looking at these numbers for 2023, the US still gets 16% of its energy from coal and 43% from natural gas, while apparently Ontario has moved away from coal entirely and only gets 27% of its energy from natural gas.

So, ya know, that’s cool. *eye roll*

But - looking at the 2011 study that compared several different types of air dryers, the high-speed airblade-style dryers still come out on top compared to paper towels, even with the United States’ fossil fuel-based energy grid, and even if 100% of the energy grid was coal-based.

It’s that standard dryer that’s so dang awful in the US…

What the heck does this all mean???

I’m not gonna lie to you, friend, after doing all this research today I kinda wish I could go back into my “air dryers have to be more sustainable than paper towels!” bubble.

But, alas, I cannot.

And now neither can you 😈 hehehehe

So instead, I’m gonna try my best to summarize everything I learned today so you can walk away from your computer or phone with an actual plan instead of overwhelm.

Here’s what we got:

• Between a standard air dryer and paper towels, paper towels are likely the more sustainable option.

• Between a high-speed air dryer and paper towels, the air dryer is likely the more sustainable option.

• In any scenario, if you’re using a paper towel, opt for one paper towel instead of two! I know sometimes the paper towels suck and you basically need two. But before immediately grabbing two, just take one and fold it in half before you start drying your hands. I’ve been using this trick for several years now and it works 9 times out of 10!

But ultimately, these choices are often completely out of our control.

When we’re in a public restroom, there’s not often a lineup of different hand drying options. You’ve usually just got one option - one type of air dryer OR paper towels.

So do me a favor and don’t stress about exactly which option is better every time.

If you happen to be a decision-maker in your office about installing paper towel dispensers or air dryers, yay!! 🥳 Use this post as a jumping off point for your research in finding the best option for your office.

But otherwise, for nearly all of us, these decisions are not ours to make.

Is this information fascinating? If you’re like me, absolutely it is.

But this is one that isn’t so much an individual consumer issue.

So don’t stress about it, okay??

Just make the best choices you can, when you can, where you can 💙

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Related:
3 Reasons to Ditch Paper Towels