# Oxygen Not Included Wiki

This article contains outdated information that is inaccurate for the current version. It was last updated for LU-356355. Unreflected changes in the discussed game mechanics are detailed here: EX1-463874
This article contains outdated information that is inaccurate for the current version. It was last updated for LU-356355. Unreflected changes in the discussed game mechanics are detailed here: EX1-463874

Thermal Conductivity is the property of a material that determines how quickly it heats or cools as it comes into contact with objects of different temperatures. Although the game states that between two objects, the lowest thermal conductivity is used, this is not true for all cases.

## Equations

The calculation of Heat Transfer in is mainly a product of:

• the Temperature difference in °C
• the passing time , which, in any case is one tick is • the applicable thermal conductivity in • is the lower of the two
• the average of the two: • is the geometric mean of the two: For heat transfer with buildings, additional factors include:

• the thermal mass of the hotter object: where is mass, is specific heat capacity (SHC), and divide by 5 if the hotter object is a building
• the buildings area
Equations 
Scenario Formula
Cell to Cell Solid → Solid Solid → Liquid
Gas → Liquid
Gas → Gas
Solid → Gas Liquid → Liquid Entity inside of a cell Entity on top of a solid cell Insulated pipe and its contents Other pipes and their contents Building and the cells it occupies Any Tiles, be they normal, insulated metal, plastic, bunker, glass or carpeted tiles, as well as doors, Farm Tiles, Heavi-Watt (Conductive) Joint Plates, and Tube Crossings count as Solid Cells, not as buildings.
Insulated Tiles reduce the thermal conductivity of their building material by (2/255)² (or 16 256) instead of 100 as stated in the game. It also uses instead of for the purpose of cell to cell conductivity, which is mostly going to be the insulated tile conductivity. Solid to gas multiplicator still apply.

Note: in real life, the units would cancel out, but surface area plays no role in ONI's calculation, therefore an additional meter needs to be multiplied to the product to have the equation result in DTU. (Not just meter, but a large string of units when calculating buildings.)

Another way to interpret this is that the units of Thermal Conductivity are given in-game as while the unit is actually interpreted as .

Recap of Cell to Cell multipliers
Gas Liquid Solid
Gas 1 1 25
Liquid 1 625 1
Solid 25 1 1

Because of the Gas to Solid x25 multiplier, it's recommended to add a double tiles layer or a thin liquid layer when trying to insulate two rooms, to instead get a x1 multiplier.

## Limits of Heat Transfer

### Lower Limits

Heat Transfer will not occur if:

• the temperature difference is less than 1 °C
• the calculated thermal flow is less than 0.1 DTU
• either of the masses is less than 1g

### Upper limits

Heat Transfer has two caps:

• If the calculated heat transfer would result in a temperature jump of more than a fourth of their temperature difference in either material. Simply said: if the temperature difference is 40 °C, a materials temperature can change at most 10 °C per tick

• If the calculated heat transfer is larger than an eighth of the total heat difference , where the total heat is a product of its temperature , mass , and specific heat capacity : . This upper limit has been removed since 509629 (Fast Friends Update). ## Thermal descriptors

There are 4 thermal descriptors in the game, and they get attached to elements when their thermal characteristic reach a certain threshold. These descriptor does not affect the element any further.

• Thermally Reactive: Elements have a specific Heat Capacity of less than or equal to 0.2
• Slow heating: Elements have a specific Heat Capacity of greater than or equal to 1.0
• Insulator: Elements have a thermal conductivity of less than or equal to 1.0
• High Thermal Conductivity: Elements have a thermal conductivity of greater than or equal to 10.0

## Tips

• When cooling or heating an area it's better to run pipes through tiles than through atmosphere. in both cases the equation for "Building and the cells it occupies" is used which multiplies both Thermal conductivities, and in general, gasses have a much lower thermal conductivity than liquids, which have lower conductivity than solids.
• However, if drastic cooling is desired, then Steam Turbines and Aquatuners will have to be involved, which means a cavity filled with Steam will have to be used.
• To jury rig insulate without building new Insulated tiles, it's therefore better to run pipes through atmosphere and have the pipes therefore changing less heat with the environment.
• Since Insulated Tiles have a factor of 1/100, and pipes a factor of 1/32, less heat is transferred if a regular pipe goes through an insulated Tile than when an insulated pipe goes through a regular Tile. Though, of course, Insulating both has an even better insulating effect.