I've seen a couple of air-blade installations, and in those they have slowed things down because paper towel dispensers allow you to take a towel, step back, and dry your hands while another person gets a towel. Rolling towels (ones where the towel is on a continuous loop) have the same issue of one user at a time.
On the other hand ever every faucet was also a drying station you've basically upped the number of drying stations tremendously and that is a win for speed.
Side benefits of keeping water off the sink/floor are good.
I wonder if we'll ever see anyone taking this to the extreme of stalls with only water and air tools for washing up (Japanese style toilets for wiping, local air-taps for your hands).
I largely agree with your points, but I wanted to point out that most modern bathrooms(and certainly not bathrooms that may have this device deployed) don't have paper towel dispensers. So it isn't a question of paper towels vs this technology, but this technology vs the hot air fan, or the dyson air blade, or other similar non-dead-tree tech
What's keeping the air from blowing droplets of water from the sink to my shirt or face?
Many people don't dry their hands at all in a public bath room (that's what god invented jazz hands[1] for).
By combining faucet and dryer you force these people into the same bottleneck as the hand-dryer users.
Those are the only scenarios where your argument holds, however.
Simply put, you are moving from 2 independent operations to 2 mutually exclusive operations – meaning that 1 sink (in the Dyson case) can only service 1 user at a time vs 1 sink+1 dryer/towel dispenser which can, at a minimum, service 2 users at once (there's actually a much bigger set of time/path calculations that could go in to this, but the simple case is enough to make it clear that your thinking is confused on this.)
Wow, great point. You're obviously unbiased! You don't even know the details of the simulation, but you're confident that you really know what's up based on your presence in "the real world".
> Many people don't dry their hands at all in a public bath room
Yes, but they still wash their hands. Many people don't dry their hands because they have to use the hot air blowers, which they know are ineffective. If they see an effective device, some members of that group will choose to use it instead of jazz handing. But even discounting those people, the wash + dry combination still works out better for most cases I can devise. The only universe I have come up with where wash and then dry else where is better than washing and drying at the same station is if there are an equal number of paper towel dispensers as there are to sinks, which has never happened in a bathroom where the number of sinks > 2, as far as I know.
> By combining faucet and dryer you force these people into the same bottleneck as the hand-dryer users.
I wasn't arguing for optimizing any one special interest groups time spent in the bathroom, I was optimizing for the total network throughput of the bathroom.
But you didn't. You have serialized access to two resources that were previously independent.
Since a significant portion of users need only one of the two resources you have created a new point of contention. For access to the faucet not only do I have to wait for people washing their hands, now I also have to wait for people drying their hands.