Question: how many calories do you burn going up 20 flights of stairs?
Answer: And yes, you do burn calories climbing and descending staircases. 0.17 calories per stair climbed, and 0.05 calories per stair descended, according to one source I found. Given there are 12 steps in the average flight of stairs, heading up and then back down would burn you somewhere between 2.5 and 5 calories.