This is Scientific American 60 Second Science.

I'm Christopher Intagiyata.

You've probably seen those little cards in hotel rooms.

Towel on the floor if you want a fresh one.

Towel on the rack if you'll use it again.

And using towels more than once means less laundry, which saves water and energy.

But you don't pay the utility bills at the hotel, so do you really care?

Well a new study in the journal Nature Energy suggests hotel guests really are motivated to

conserve for factors other than money.

The study actually shows that even if people have zero financial benefits,

they still respond to this kind of feedback for environmental reasons.

Varenit-Evenbach studies information systems research and behavioral... for environmental Lodger energy use issue by installing smart shower meters in six Swiss hotels,

265 rooms in all. The meters displayed an ongoing tally of water and energy use

as guests were washing up. 20,000 showers later, the scientists found that their simple intervention encouraged guests to use 11% less energy per shower.

That's compared to guests in a control group who simply saw the water temperature displayed on the meter.

This finding probably won't revolutionize the bottom line for hotels though.

Each smart meter would save a hotel only about 20 bucks a year.

But in homes, where most people take most of their showers, the savings actually could

add up for the individual, and devices like these could help consumers focus their efforts where they

matter most. Most people think that they should switch off the lights, which isn't

the most active thing to do and they don't know that the actual big end users would

be space heating and water heating.

...