In Fallout: Shelter, managing the three available resources (Power, Food, Water) is an important mechanic. However, I'm not quite sure what determines the usage of these resources.
For food and water, I would expect it to be based on the amount of dwellers in the entire vault. However, it doesn't sound completely unreasonable that the function of some rooms may increase water usage.
What is food and water consumption based on?
Power ought to be tied to the production that goes on in the vault. But it isn't clear if empty rooms use power at the same rate as rooms being used (or at all). If so, the advice commonly given to not get too many dwellers too quickly could also hold true for rooms. Also, elevators may or may not use power.
How is power usage determined?