Potential Energy

I recently spend a few days visiting a client whose office was on the second floor of a building. I generally just took the stairs up and down, but a majority of the people in this office seemed to prefer the elevator.

I generally feel a slight sense of superiority over (and contempt towards) people who routinely use the elevator for one or two flights. Why squander all that mechanical power and energy for such a trivial task, particularly one offers a mild bit of exercise as well? (Not to mention, the stairs are almost always faster!)

One day I was heading out to lunch, and just as I stepped in the lobby, I saw two people getting on the elevator to go down. They offered to hold the door, and I said, "No thanks, I'm using the steps." And then it occurred to me: was I wasting energy by taking the stairs? Presumably elevators are counterweighted against a "typical load", so if the weight of the car and two riders is less than the counterweight, lowering the car actually means extra work to lift the counterweight. There would be a fixed amount of energy opening and closing the doors and just making the pulleys go round, etc, but this elevator's making the trip with or without me.

So, would I have actually saved the elevator a small bit of energy by riding it?