A House (or Home) is a structure built by the player that Town NPCs require in order to spawn, with one House required per NPC. A structure must meet several requirements in order to function as a House (see details below). You can check if a structure meets the requirements by using the Housing Menu's top button, labeled with a question mark ("?"). NPCs generally retreat to their Houses at night and remain in them until dawn. They will also retreat to their houses during a Solar Eclipse (since 1.2.3).
The Angler, Goblin Tinkerer, Mechanic, Stylist and Wizard will each make their initial appearances regardless of available Houses. Once initially found, each will require a House in order to respawn subsequently.
A house must be fully enclosed:
- The side walls (vertical blocks) can be made of blocks, doors or wood platforms.
- The floor and ceiling (horizontal blocks) can be made of blocks or wood platforms.
- The NPC needs at least one solid (non-platform) block to stand on at night. This block may not be directly adjacent to either of the walls of the house.
Including the frame (floor, side walls, and ceiling), a House must have at least 60 total tiles, but less than 750.
Additionally, a House's outer frame must meet one of the following minimum dimensional requirements:
|Excluding ceiling, floor and walls||Including ceiling, floor and walls|
|3 tiles wide x 10 tiles high||5 tiles wide x 12 tiles high|
|4 tiles wide x 8 tiles high||6 tiles wide x 10 tiles high|
|6 tiles wide x 6 tiles high||8 tiles wide x 8 tiles high|
|7 tiles wide x 5 tiles high||9 tiles wide x 7 tiles high|
|8 tiles wide x 4 tiles high||10 tiles wide x 6 tiles high|
|10 tiles wide x 3 tiles high||12 tiles wide x 5 tiles high|
 Background Wall
A house must have a background wall in order to be suitable. Any walls crafted or mined by the player are valid.
- Walls not placed by a player (such as naturally-occurring dirt walls) do not count, with the exception of those generated in Floating Island structures, the Planked Walls found in Underground Cabins, the Living Wood Walls in Living Tree rooms, or the Sandstone Brick Walls found in Pyramid structures.
- Background walls may contain holes if the holes are no taller or wider than four tiles. (e.g. 4 background tiles across or tall, so the maximum size is 4x4, 16 in total. The hole cannot exceed 4x4 or 16 tiles.). Walls may have multiple holes as long as they are separated by at least a single tile of background walls.
- Having background holes may sometimes allow monsters to spawn within the House. To create windows more safely, place sections of Glass Wall instead.
A House must have at least one valid Light Source, Flat Surface item, and Comfort item placed within it. The items listed below will fulfill these requirements.
- Not every item that provides light will fulfill a House's light source requirement. You must use one of the items listed below.
- Any type of each item listed below will fulfill the requirement. For example, any color Torch will work, as will any theme of Chair.
If a House is located near Corruption or Crimson, it may become uninhabitable. If these spread near an occupied House, the NPC living there may move out and wander the area until a new House becomes available.
A House is considered corrupted based on its "Corruption rating," which calculates all tiles in a 45-block "radius" around the house; a house's Corruption rating must be 250 or less. This is about half the blocks in the radius.
- Each tile of Ebonstone, Ebonsand, and Corrupted vines & plants increases a House's Corruption rating by 1. Conversely, each sunflower reduces a House's Corruption Rating by 5.
- Each tile of Hallowed grass, Pearlsand, and Hallowed plants reduces the rating by 1.
 Simplest valid option
- 25 Dirt Block for floor, wall and ceiling.
- 32 Dirt Wall (8 Dirt Block) for background wall.
- Wooden Door (6 Wood). Can be replaced with one Wood Platform.
- Wooden Chair (4 Wood).
- Wooden Table (8 Wood).
- Torch (1 Wood, 1 Gel, results 3).
Summary raw materials:
- Houses may be attached together and share common walls, floors, ceilings, and doors.
- If a House with an assigned NPC is destroyed or any of its requirements are invalidated, the NPC will wander the area until a valid House becomes available again. If killed, the NPC will respawn once a valid house is restored.
- An NPC will not spawn within its House if that House is on the visible screen at the time, and may walk around the area outside instead. Quitting and restarting in single-player mode will place the NPC in its house. At night, NPCs will be automatically placed inside their Houses if the player travels several screens away, or if the player uses a Magic Mirror or Teleporter.
- In single-player, a total of 19 NPCs (20 during the Christmas season) will eventually become available to a player in an ordinary biome who fully advances through the game. It may be worth building a structure containing 19 rooms (or 20 if during the Christmas season) that meet the House requirements when planning a headquarters. The Truffle is an additional 20th NPC (or 21st, if during the Christmas season), but must be in a surface mushroom biome, and will likely need to be housed separately from the player's main structure.
- The side, top, and bottom of the world do NOT count as walls.
- If a stone wall has been converted into Pearlstone Wall, the House will become invalid.
- If building a house at a world's original spawn point, be careful to not place any foreground objects or blocks where characters appear. This will delete the object(s) and/or block(s) the next time a character spawns there.
- Placing a light source in a Living Tree room or Floating Island structure will cause it to become suitable housing, unless you have removed its furniture.
- If you wish to prevent NPCs from wandering around, place a torch on the ground on each side of the door (it does not necessarily have to be on the ground since 1.2). It will not only count as a light source but also prevent the NPC from leaving. Keep in mind this will also complicate opening the door for the player, as you will need to face away from the door to open it or right-click the torch and re-place it when you want to enter. Wooden Beams and Wood Platform can work just as well.
- 220.127.116.11: Opening doors will no longer cause a room to be unsuitable.
- 1.2: Fixed a bug that would cause a suitable house to be unsuitable.
- 1.1: There is now a built in interface for checking if a house is valid for being moved into and designation the specific house for the specific NPC.
- 1.0.6: Requirements modified; may now use a bed, toilet, throne or bench instead of a chair, and may use a dresser, bathtub or bookcase instead of a table or workbench.