Fallout – How to build 643 rooms in Fallout shelter

This happened to me when I left the game mid-raider attack. I wasn't able to log back in for a few hours and when I did, the same thing happened (loss of people/resources/happiness).

I have not read any 'official' comments regarding this, but leaving the game during any event causes the dwellers not to respond properly.

Just got a loading screen tip in the game (the wording may not be exactly the same, but the general meaning should):

Dwellers run on food and water. Rooms run on Power.

This is certainly an official source, although not a very in-depth explanation. From this, one could draw the conclusion that rooms consume power regardless of occupancy, and only dwellers use water, even if this isn't explicitly stated.

To further investigate the details (unless some other source is available), I suppose someone will have to do some science.

Edit: It appears the good folks over at /r/foshelter/ have done quite a bit of science.

Some key points relating to the resource consumption (not absolute facts, but probably close to the truth):

• Food/Water consumption is 21/hour per dweller in the vault (so explorers don't count). This means a L3 full-size Nuka-Cola plant can supply 100 people with food and water.
• Power consumption is a bit more complex, and isn't fully explored yet, but it seems to change with the level of rooms. Still unclear if elevators and other things consume power. For now though, don't build more/larger rooms than you need if power is an issue.

There are a lot of other interesting points made in the thread linked above, so I really recommend checking it out. More detailed information is available here. If they keep the work up, this may be the go-to resource for data on the game.