Editing Temperature

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'''Temperature''' management is an important part of a productive colony. Temperature mostly affects pawn mood, food and corpse spoilage, and plant growth. Too hot or cold may lead to [[hypothermia|fatal]] [[heatstroke|conditions]], even to animals.  

=== Measuring temperature ===
Players can switch the in game display to Celsius (°C),  Fahrenheit (°F), or Kelvin (K). This Wiki will list values in both Celsius and Fahrenheit. Kelvin is the same as the Celsius scale, but shifted by +273.15°. Using Kelvin is not recommended for those who are unfamiliar with it, and isn't covered in this article.

Internally, the game uses Celsius (°C) for all temperature functions, such as "too hot" or "too cold". As the game always rounds temperature to an integer ("whole number"), you can get a misleading indicator while using Fahrenheit. This inaccuracy normally isn't big, around 0.3°F. But if you want reliable temperature values, and ''especially'' if you are [[modding]], use Celsius or Kelvin.

== Temperature changes ==
The maximum temperature is {{Temperature|1000}} and the minimum is {{temperature|-270}}, very close to [[Wikipedia:absolute zero|absolute zero]]. The minimum temperature is not encountered during normal gameplay, but [[fire]]s in small enclosed spaces can reach the maximum temperature.

=== Outdoors vs indoors ===
Outdoor temperature usually fluctuates slowly by day and season and is bounded by the climate of your [[biome]]. Be careful though, because unpredictable [[events]] like a [[cold snap]], [[volcanic winter]] or [[heat wave]] can also change outdoor temperature unexpectedly. No amount of added heat, even with [[development mode]], will affect or change the outdoor temperature. Otherwise, the outdoors is simply treated as another room, albeit a large one.

A place completely enclosed in [[wall]]s, [[door]]s, and other "impassible" objects are considered a [[room]], or "Indoors". Corners are not required to create a room. Passible objects like [[sculpture]]s or [[sandbag]]s will not create a room. If a place is ''not'' considered a room, it is considered "Outdoors". In addition, rooms that are ''Unroofed'' - having less than 75% [[roof]] tiles - are considered fully outdoors for the purposes of temperature.

Outdoors and unroofed areas will always have the outside temperature, no matter what. By turning a place from Indoors to Outdoors, it will instantly become the outdoors temperature. This is caused when any wall or door that borders the outside is destroyed or deconstructed. Opening a [[door]] or [[vent]] is not enough for instant equalization. However, doors and vents do make heat transfer faster.

Rooms that are ''fully roofed'' are entirely subject to heat changes. Removing roof tiles will cause temperatures to "equalize" with the outside. A room that is less than 75% roofed will remain at outdoors temperature. 

=== Heat transfer between rooms ===
Temperature change ''within'' a room is instant. 

Heat will also transfer from enclosed rooms to other rooms, and the outside. Heat travels through roofs, walls, and doors. Heat transfer from walls only occurs in cardinal directions. Thus the corners of rooms can be eliminated with minimal effect.  Open doors and open roofs will quickly "equalize" temperature to whatever's on the other side. Adding another layer of walls increases insulation, but only up to 2 layers of wall. Gaps between each layer will decrease the insulation, but still have an effect.

Larger rooms have more thermal "mass", and their temperature changes more slowly than smaller rooms, but temperature equalization with the outside is proportional with a room's perimeter. A square (shape with the most volume/perimeter) will lose heat slower than thin, rectangular hallways. Rooms with more wall tiles exposed to the outside will lose temperature faster. Open [[door]]s and [[vent]]s will help transfer heat faster, if so desired.

See the [[#Temperature mechanics|temperature mechanics]] section further down for more details.

== Summary ==
Temperature has the following effects on:

=== Crops ===
All [[biome]]s have a listed growing season. Some are very short (or, in extreme cold, non-existent) and others are "year round". Crops will die, and colonists will avoid planting outdoors, if it isn't growing season. Many players pick their starting location based on this, with year round being the easiest option.

However, a year round climate is no guarantee of trouble-free farming experience. Just getting close to freezing will slow plant growth, reducing the output of crops. Moreover, climates that do not freeze tend to get ''very'' hot in the summer season, hot enough to kill crops in some instances. [[Cold snap]]s can drop the temperatures below freezing for short periods - but long enough to, again, kill crops.

The short-term solution is to immediately harvest everything to save what you can. The long-term solution is some sort of greenhouse, making use of temperature controlled indoor structures, walled and roofed, with [[heater]]s or [[cooler]]s, [[sun lamp]]s, and possibly [[hydroponics]].

=== Food ===
Warm temperatures rot food, corpses, and certain plant matter like [[psychoid leaves]] and [[herbal medicine]]. Even "durable" foods like corn and rice will eventually rot away. Colder temperatures preserve food and corpses by slowing spoilage. Freezing temperatures stop spoilage entirely and preserve these items indefinitely. [[Cooler]]s will preserve food, so colonists starting with Electricity will quickly want to build a dedicated room. When freezing a room, watch out for [[heat wave]]s.

Fertillized [[egg]]s will be "ruined by temperature" when left long enough outside of its comfortable range of {{Temperature|0|50}}. "Ruined" eggs may still be eaten as normal, but won't hatch into an animal. In a similar vein, a [[fermenting barrel]] must be kept in a comfortable range between {{Temperature|{{Q|Fermenting barrel|Min Safe Temperature}}|{{Q|Fermenting barrel|Max Safe Temperature}}}} for [[beer]] to be produced.

[[Deterioration]] is an entirely different mechanic, and items left outside will lose health regardless of temperature. Rotting isn't influenced by and has no effect on an item's hit points.

=== Creatures ===
{{Stub|section=1|reason=Burn/Frostbite chances}}
{{Main|Heatstroke|Hypothermia}}
Pawns have a [[Maximum Comfortable Temperature]] and [[Minimum Comfortable Temperature]]. Going over {{Temperature|10||delta}} beyond these limits will start giving them [[heatstroke]] or [[hypothermia]]. The further above or below this {{Temperature|10||delta}} limit the faster the Heatstroke or Hypothermia rises. At {{Temperature|150||delta}} above their comfortable temperature range, creatures will begin to take burn damage. If Hypothermia reaches a severity of 37% and the pawn is in a location at {{Temperature|0}} or below, there is a chance the pawn takes Frostbite damage. The higher the Hypothermia severity the higher the chance of Frostbite damage. [[Insectoid]]s will experience [[hypothermic slowdown]] instead of hypothermia. Pawns will also receive negative [[mood]]lets based on how extreme the temperature is. The Gear tab shows aggregate stats about comfy temperatures.

Hypothermia and Heatstroke are both fatal at 100% severity. Though, both Heatstroke and Hypothermia have significant health consequences and can lead to death before the 100% severity level is reached.

For humans, [[apparel]] will increase both comfortable thresholds, [[Apparel#Insulation|depending on the apparel type and material]] (e.g. [[wool]] [[parka]]s insulate well against cold). Colonists will try and wear items suitable for the temperature, unless they are forced otherwise. Colonists' moods ''ignore'' apparel when considering sleeping moodlets. So piling on the warmest apparel doesn't avoid a "Slept in the cold" bad thought if a bedroom is not adequately heated.

Animals tend to have much higher comfortable thresholds. However, in extreme [[biome]]s, it may be necessary to build a "barn" of some sort with temperature control and designate indoor [[animal sleeping spot]]s to keep your herd warm/cool.

Many work benches, such as a [[electric stove]] or [[stonecutter's table]], have a comfortable range between {{Temperature|10|35}}. Above or below this range, the ''bench'''s work speed is multiplied by {{Bad|70%}}.

=== Fire ===
{{Main|Fire}}
Fire is a destructive force capable of destroying plants, buildings, and pawns alike. Pawns and items can spontaneously ignite when temperature is at or above {{Temperature|235}}. Fires can spread via embers from up to 2 tiles. 

Fire itself provides a massive amount of heat.

== Managing temperature ==
Temperature management is important for any colony, regardless of climate. It can be simply managed with a good power supply and the following structures. Temperature changing buildings will still work while "outdoors", but have no noticeable effect.

=== Temperature thresholds ===
{| class="wikitable"
! Temperature !! Effects
|-
| style="text-align: center;| {{Temperature|1000}} || Maximum value
|-
| style="text-align: center;| ~{{Temperature|235}} || Items spontaneously catch fire
|-
| style="text-align: center;| {{Temperature|60}} || Maximum comfortable temperature of any animal ([[Dromedary]] / [[Insectoids]] / [[Iguana]])
|-
| style="text-align: center;| {{Temperature|44}} || [[Plants#Temperature|Plant growth]] slowed
|-
| style="text-align: center;| {{Temperature|35}} || At this temperature and above work benches show "Bad temperature" and Work Speed is reduced to 70%.
|-
| style="text-align: center;| {{Temperature|30}} || [[Campfire]] max temperature
|-
| style="text-align: center;| {{Temperature|26}} || Default [[human]] upper comfort limit without clothing modifiers.<br/>Sleeping above this temperature creates "Slept in the heat" thought in baseline humans.
|-
| style="text-align: center;| {{Temperature|23}} || [[Torch lamp]]/[[Fungus darktorch]]{{IdeologyIcon}}/[[Darktorch]]{{IdeologyIcon}}/[[Brazier]]{{RoyaltyIcon}}/[[Darklight brazier]]{{RoyaltyIcon}}{{IdeologyIcon}} max temperature
|-
| style="text-align: center;| {{Temperature|21}} || [[Heater]] and [[Cooler]] default target
|-
| style="text-align: center;| {{Temperature|17}} || [[Passive cooler]] min temperature
|-
| style="text-align: center;| {{Temperature|16}} || Default [[human]] lower comfort limit without clothing modifiers.<br/>Sleeping below this temperature creates "Slept in the cold" thought in baseline humans.
|-
| style="text-align: center;| {{Temperature|10}} || Below this value [[Plants#Temperature|plant growth]] and food spoiling slowed.<br/>Food spoiling between 10C and 0C is multiplied by a factor of (Temp)/10, in Celsius.<br/>Below this value work benches show "Bad temperature" and Work Speed is reduced to 70%.
|-
| style="text-align: center;| {{Temperature|9}} || Food spoiling rate multiplied by a factor of 0.9, or time to spoil multiplied by 1.11.
|-
| style="text-align: center;| {{Temperature|8}} || Food spoiling rate multiplied by a factor of 0.8, or time to spoil multiplied by 1.25.
|-
| style="text-align: center;| {{Temperature|7}} || Food spoiling rate multiplied by a factor of 0.7, or time to spoil multiplied by 1.43.
|-
| style="text-align: center;| {{Temperature|6}} || Food spoiling rate multiplied by a factor of 0.6, or time to spoil multiplied by 1.66.
|-
| style="text-align: center;| {{Temperature|5}} || Food spoiling rate multiplied by a factor of 0.5, or time to spoil multiplied by 2.
|-
| style="text-align: center;| {{Temperature|4}} || Food spoiling rate multiplied by a factor of 0.4, or time to spoil multiplied by 2.5.
|-
| style="text-align: center;| {{Temperature|3}} || Food spoiling rate multiplied by a factor of 0.3, or time to spoil multiplied by 3.33.
|-
| style="text-align: center;| {{Temperature|2}} || Food spoiling rate multiplied by a factor of 0.2, or time to spoil multiplied by 5.
|-
| style="text-align: center;| {{Temperature|1}} || Food spoiling rate multiplied by a factor of 0.1, or time to spoil multiplied by 10.
|-
| style="text-align: center;| {{Temperature|0}} || Plant growth and food spoiling stopped.<br/>[[Toxic wastepack]]s{{BiotechIcon}} do not dissolve. (They can still [[deteriorate]])
|-
| style="text-align: center;| {{Temperature|-10}} || Most plants die.
|-
| style="text-align: center;| {{Temperature|-65}} || Minimum comfortable temperature of any animal ([[Thrumbo]])
|-
| style="text-align: center;| {{Temperature|-270}} || Minimum value.
|}

== Cooling buildings ==
=== Passive cooler ===
[[{{Q|Passive cooler|Image}}|56px|left|link=Passive cooler]]
The [[passive cooler]] is a very low-tech option automatically unlocked for all default starts. They operate at the same strength as a Cooler and will cool rooms to a very comfortable {{Temperature|15}}. Passive coolers last for 5 days; it needs to be fueled with [[wood]] when it runs out of fuel. Due to the temperature limit, passive coolers are unable to preserve food.

Passive coolers are a life saver in extremely hot climates as they can be quickly built, are immune to electrical events and are easily massed in a heat wave. Use passive coolers to keep your living spaces survivable and chill rooms surrounding a freezer to further protect the products inside.
{{clear}}

=== Cooler ===
[[{{Q|Cooler|Image}}|56px|left|link=Cooler]]
The [[cooler]] is primarily used to lower the temperature of a room. It has two states of power consumption: low and high. In its low state, the cooler produces no heat or cold but still requires 20 W. It can be used to lower the temperature of a room to a comfortable {{Temperature|20}} (room temperature) in the summer or create a walk-in freezer for your food. In hot biomes such as desert or rainforest, having comfortable air conditioning is a necessity for any base.

Coolers are heat pumps that produce both a cold side ''and'' a hot side. The hot side is rarely useful and should be directed to an outdoor space (or a 1x1, unroofed room) to not inconvenience your colony. The heating side is useful when outdoors temperature is uncomfortable, but not freezing. This is between {{Temperature|1|16}}, but in practical terms, you should point the heat side at the colony when the outdoors temperature rarely goes above {{Temperature|20}}. Never block a cooler's intake or exhaust port, or else it won't function. 

A cooler is theoretically able to cool a single square by about 1800 kelvin [K]. But this is not a linear relation, as a room always exchanges heat with adjacent rooms and/or the outside.

==== Analysis ====
Electric coolers are the only way to create freezers. Building one is as simple as making a room and replacing some wall tiles with coolers. Direct the cold "blue" zone of the cooler inside the room and the hot "red" tile to an outdoor area. Reduce the cooler's target temperature to below {{Temperature|0}}. As the room cools down any food left inside will decay more slowly until it freezes. Frozen food will stay fresh indefinitely and incurs no other benefit or penalty when eaten.

If your freezer area is more than about 50 squares, and/or you are living in an area with a hot summer, you will want 2 coolers (and perhaps more, see "adding coolers", below).  Put one at 0, and the other at -2. With double walls, this will let one cooler "idle" at 20 W of power in cooler weather while the other easily keeps things frozen, but be available to help when needed for warmer weather. [[Battery|Batteries]] are useful for power outages; you may want to keep charged batteries disconnected via [[power switch]] for these situations.

Freezers lose heat through walls and doors. The material of a wall doesn't matter, but for maximum insulation, you should put a double layer of them. Doors will cause heat loss when opened. This loss can be offset by having doors arranged in sequence, one after another, at points of egress, in an "airlock" like fashion. The loss can be examined by mousing over the sections of the airlock to see the temperature. Using [[door]]s rather than [[autodoor]]s can help reduce the cooling lost, though this slows down colonists. 

==== Adding coolers ====
There may come a moment when you realize ''"I don't have enough coolers for this area..."''. If the weather is cool, that's not a big problem, but it's more likely that the weather will be brutally hot when you realize this. And it's also likely that it's your freezer that's not at "freezing" (since colonists can tough it out). If you open a wall to put in an additional cooler, your freezer immediately rockets to "outside" temperatures - which is probably a dealbreaker, rotting all your frozen items. So here's what you do...

Decide where in the current wall you will put your new cooler, and build a door ''outside'' where you will tear the existing wall down (you don't need "side walls" to support it).  (A wall would "block" the cooler exhaust and prohibit construction, but a door will not!)  Then, [f]orbid the door (so it doesn't get opened), and deconstruct your wall; the new door will maintain the area as "inside". Then build your cooler (remembering the orientation, warm side "out"). Once the new cooler has been installed, deconstruct the door, and you're done.

== Heating buildings ==
=== Campfire ===
[[{{Q|Campfire|Image}}|56px|left|link=Campfire]]
{{#show: Campfire | ?note }}
Campfires are a quick and dirty solution to produce heat in a hurry. They require no energy, but are temporary structures and must be refreshed with wood every few days. Otherwise, they produce the same amount of heat as an electrical heater. They cannot raise the temperature to over {{Temperature|30}}. They can't be controlled, so may make pawns uncomfortably hot - open doors or roofs to lower heat..
{{clear}}

=== Heater ===
[[{{Q|Heater|Image}}|56px|left|link=Heater]]
The [[heater]] is used to raise the temperature of a room. It has two states of power consumption: low and high. In its low state, the heater produces no heat but still requires 18 W. It can be used to raise the temperature of a room to a likable {{Temperature|20}} (room temperature) in the winter or create a walk-in heat trap for your foes. In any cold biome, such as the Tundra, the heater is a necessity for any base.

A heater (in theory) is able to heat a single square by about 1800 kelvin [K]. But this is not a linear relation as a room always exchanges heat with adjacent rooms and/or the outside. This heat conduction effect can be pretty noticeable in extremely cold or hot environments.
Example: In a realistic setup, this means it can heat a room with 50 squares by an average of about 36 K per square.
So a room with 50 squares and an outside temperature of {{Temperature|-10}} can be heated up to comfortable {{Temperature|26}} or something near that with a single heater.

== Incidental heat ==
=== Generators ===
[[{{Q|Chemfuel powered generator|Image}}|56px|left|link=Chemfuel_powered_generator]]
{{#show: Generators| ?note }}
Generators produce a non-negligible amount of heat for the room they occupy, especially when placed in numbers.
If placed strategically, you can reduce the number of heaters and coolers necessary to manage the temperature in your base.

It's also worth noting that generators will continue to produce heat (and burn fuel) during solar flare events. If your colony is in a very cold climate, this can be used to ensure that critical sections such as hydroponics or barns for sensitive animals don't lose all their heat in a power outage.

=== Steam geysers ===
[[File:Steam geyser.png|56px|left|link=Environment#Steam geyser]]
A steam geyser will heat up a roofed room even when covered with a [[geothermal generator]]. They are extremely useful for staying warm in frozen climates, but can overheat an indoors space in warmer biomes.

=== Fire weapons ===
[[{{Q|Molotov cocktail|Image}}|56px|left|link=Molotov cocktail]]
{{#show: Molotov | ?note }}
Weapons that generate fire such as [[molotov cocktail]] and [[incendiary launcher]] can be used to quickly generate heat inside your colony. Under normal conditions this is a '''bad idea''' because fires will quickly bring your base to intolerable temperatures. However in a bitter arctic climate with no wood and inadequate heaters, these weapons are your last defense against freezing to death. Draft your colonist and force them to open fire on an empty space, or burn spare corpses and rags to increase heat output.


=== Solar pinhole ===
{{Royalty|section=1|no category}}
[[File: SolarPinhole.png|64px]]
[[Psycasts#Regular_psycasts|Solar pinhole]] is a psycast that creates heat and light. It lasts five days. It is useful for emergency situations, such as power shortages during [[Events#Cold_snap|cold snaps]].

== Heat transfer ==
=== Vent ===
[[{{Q|Vent|Image}}|56px|left|link=Vent]]
{{#show: Vent | ?note }}

Vents can have any building in front of it, but no walls. Vents work best when connecting directly to a climate controlled room. Trying to chain vents across smaller rooms will lead to each successive room getting less effective climate control, and connecting to a hallway won't work well if the hallway is blocked with doors. A vent can be designated to be closed, an action carried out by colonists assigned to [[Work#Basic|Basic]].

=== Doors ===
[[{{Q|Door|Image}}|56px|left|link=Vent]]
Similar to double thick walls, double doors (not side-by-side, rather, both in the path of travel) improve insulation and reduce temperature equalization.
A door can be left permanently open (mark the door to 'hold open' and have a pawn pass through) to help control temperature. Open doors allow temperature to more quickly equalize between rooms or the outdoors. Equalization through open doors is less potent than vents.

== Temperature mechanics ==
Equalization calculations happens once every 120 game ticks.

Temperature seems to be measured to an extreme precision. A outdoor of {{Temperature|-9}} and a room of {{Temperature|2000}} have a difference around -9555.292C

=== Passive equalization ===
This is equalization via walls and roofs.

'''Walls''' will equalize towards the room on the other side. This can be another fully realized room or simply the outdoors. If the other side is not outdoors, that room will also equalize towards this room. 

* The material of the walls does not matter. Wood is as isolating as any stone or metal. And unmined rocks are equally effective.
* The surface area does seem to matter. Basically, the game is using a 2D variant of the [[Wikipedia:square-cube law|square-cube law]], with walls taking the place of "surface area" and room size taking the place of "volume". As such square rooms are the most efficient at keeping temperatures.
* A 2nd layer halves the temperature equalization via walls. Adding more than a 2nd layer of wall does not seems to have any effect.
* Furniture acts highly variable for this and even just the definition what is a room. Nutrient dispensers are one of the few items working fully like walls for equalization purposes

Example wall equalization values at -9555.208C difference:
* 1x1: -161.470°C
* 2x2:  -81.235°C
* 3x3:  -54.157°C
* 4x4:  -40.618°C
* 5x5:  -32.494°C
* 6x6:  -27.078°C
* 7x7:  -23.210°C

Example double wall equalization values at -9555.208C difference:
* 1x1: -81.234°C
* 2x2: -40.617°C
* 3x3: -27.078°C
* 4x4: -20.309°C
* 5x5: -16.247°C
* 6x6: -13.539°C
* 7x7: -11.605°C

'''Roof''' is a major part with equalization with the outdoor temperature. It will always equalize with the outdoor temperature, regardless what the room borders. However, the equalization rate is also constant for all room sizes at the same temperature difference. There are 4 basic types of roof:
* unroofed
* Constructed (Thin Roof)
* Thin Rock (Thin Roof)
* Thick Rock

* Thin Roof at a difference of -9555.208C it is -57.331°C.
* unroofed tiles are looked at in relation to the total count of roofed tiles. With at least 1/4 unroofed the room will simply equalize to outdoor temperature on the next tick. 
* thick roof isolate the same as thin roof. However, they also add a cooling effect if indoor temperature is above about {{Temperature|15}}; this effect is extremely small compared to other sources, however

=== Active equalization ===
While Vents, Coolers and open doors still keep rooms separated, they also equalize temperature at a very high rate. This rate is unfortunately not shown on any tooltip.

Torches, Campfires, Heaters and Passive coolers will directly modify the room temperature instead, adding/removing heat every equalization tick as appropriate for their settings/current state.

== Version history ==
* [[Beta 19]]/[[Version/1.0.0|1.0.0]] - Equalized [[mood]] penalties for being too hot and too cold.
* [[Version/1.3.3066|1.3.3066]] - Fix: Changing temperature display mode (C to F) doesn’t update temperature readout immediately.

{{Nav|temperature}}
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