Do elevators use power in Fallout Shelter?

I have a vault with only 4 layers and built a column of elevators down to the deepest level. I did not notice power usage increase of any significant amount.

I conclude from anecdotal experience that elevators effectively do not use any power.

Elevators do not cost any power. You can see the actual numbers of your power/water/food consumption by tapping on them. See the below images for before and after adding 2 elevators to the beginning of a new vault.

As you can see, the vault still had the same power requirements/maximum, and the slider bar of minimum power required didn't move. It's the slider bar that shows the requirement (ie below that and you start to lose power), so if the slider bar doesn't move when you add an elevator, then it doesn't require any additional power.

Edit: I should point out that I'm aware that the numbers themselves do not indicate this -- they are merely a record of current and available power and speak nothing about how quickly it's used.