Our colonies are advanced enough to have auto-doors and auto-turrets, how bout auto-lights! Colonist walks into an area, and the lights turn on, when no colonists are present or they are sleeping they turn off.
I always seem to avoid building lights in bedrooms and other rooms that are not constantly occupied simply to conserve power. I propose they would cost slightly more power (200 vs 150) while on, 10 power while off (to monitor for movement).
This would also be nice if it was applied to colored lights as well.
Try the PowerSwitch (https://ludeon.com/forums/index.php?topic=2890.0) Mod. It should have the things you want.
In terms of efficiency, there is no point in having lights anywhere except crafting rooms, eating/table rooms and kitchens. Colonists generally don't stand still long enough anywhere else to get the darkness debuff, and they don't care about it if they're sleeping.
Personally, I'd like the darkness debuff to ramp up over time, as it's a very small penalty that can almost always be ignored. In fact, colonists with a darkness phobia trait would be awesome. In the current game, lights are mainly for cosmetics and lighting up targets.
Yup, this is exactly what I was looking for and a little more. thanks.
How about characters walking slower in dark indoors ? You could also add a new trait - "afraid of darkness".