Vault dwellers ( Fallout Shelter ) Vault dwellers are the inhabitants of the player ' s vault and as such are a very valuable resource . They are the ones who do the work , making the power , water and food that the vault requires to survive . They are also are sent out into the wasteland to explore for supplies . Ensuring their happiness and safety should be one of the overseer ' s primary concerns . Vault dweller statistics . All dwellers have their own set of SPECIAL statistics , thus assisting in determining their ideal job posting . Each of these need to be considered to help achieve peak output in the production rooms . For example , if a person with a Perception of 1 is posted in the water treatment room instead of a person with a Perception of 6 , production will be poor and minimal . Also , placing the right dwellers in the right places helps fulfill objectives . One can always modify a vault dweller ' s SPECIAL stats by equipping an outfit that modifies SPECIAL to achieve the desired effect . Acquiring and losing vault dwellers . Players begin with 12 vault dwellers , all of which start at Level 1 . Acquiring . Players can acquire new vault dwellers by : If the player ' s vault has no room for a new dweller ( either because insufficient living quarters have been built , or the vault has the maximum of 200 dwellers ) , pregnant women will not give birth and new arrivals will not enter the vault . Dwellers that have been sent out to explore the wasteland still count against the total capacity of the vault . Eviction . Players can reduce the number of dwellers by death or expulsion . Death can happen inside the vault during incident s or outside the vault by running out of stimpaks while exploring or getting killed on a quest . Moving vault dwellers . When a dweller is dragged into a room , they will commence whichever activity is appropriate for that room : for instance , a dweller dragged into a power plant will activate its power - producing abilities . A dweller dragged into a training room will begin training in that SPECIAL ability . If a dweller is dragged into a room that is already full , they will take the place of the person there with the lowest ( random if many ) applicable SPECIAL statistic . For instance , if a dweller on coffee break is dragged into a 2 - room power plant that already has 4 dwellers in it , the dweller with the lowest Strength score ( including outfit boost ) will leave and will go on coffee break . The stats which are not applicable to that room are not taken into account , so if two dwellers in a power plant have the same strength , but one has higher agility , which one gets replaced is randomly chosen as their agility is irrelevant . A dweller dragged into a production room will gain levels as they produce the appropriate resource . The speed at which they gain this is determined by the size of the room , the number and level of other dwellers in with them , and how often the room is rushed successfully . Improving vault dwellers . Common dwellers who arrive at or are born into the vault start at Level 1 . Those who are born from parents with high S . P . E . C . I . A . L . statistics and level have a chance that their own statistics may be greater than 1 . Dwellers in a training room will increase the appropriate SPECIAL statistic for that room . For instance , a dweller in an armory will increase their Perception skill . When they have gained a point , they will show a small icon over their head , which must be cleared for the next level of training to begin . While they are training , they will show the time remaining until the next point gain under their feet . One must zoom in all the way in order to see time remaining under each training dweller . Dwellers in training can only improve each SPECIAL statistic to 10 . A dweller that has reached 10 in that specific statistic ( e . g . a dweller in the armory who has reached a Perception score of 10 ) will then show " Max Level Reached " under their feet , instead of the time until the next upgrade . If a dweller is dragged into a room while an incident is occurring , they will run back to their previous location or role once the incident is over . This can be useful for putting two heavily armed and armored vault dwellers in the vault entrance to meet raiders , knowing that they will return to their day jobs once the excitement is over . Moving dwellers for other reasons during an incident will have the same result . Separating a dancing couple during a fire to stop mating from occuring , for example , will be ineffective , as they will return to the mating process once the fire has ended . Happiness . Happiness is an important factor in keeping a vault functioning at peak efficiency . There are several ways of keeping vault dwellers happy :