From Arashi no Shukudai kun with Mao Kobayashisan and Hatori Shinichi.
Hatori: Do you do "ECO" Nino?
Nino: Well, when I'm at home and when the vibe is good, I don't turn even a single light on.
Hatori: When the vibe is good?!
Nino: When the sky's clear you can see things clearly (without lights on).
Hatori: O! About visibility!
Nino: I get my light from the street lights so I just open all my curtains.
*hahahahaha... ECO? or cutting down on eletric bills?! lol.*