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Overheating (sometimes also called overloading) a module allows you to get more output from it for a short time. As the name suggests, overheating isn't something you can do indefinitely. Eventually you will burn your module out, making it inoperable.

However, if used with care or in an emergency, the benefit gained from an overheated module could be the difference between losing your ship and killing your enemy. Good pilots know when the risk is worth the possible reward.

Overheating -- and knowing how and when to do it -- is a very important skill in small fleet and solo PvP.


Overheating in action. The repper in the lowslots is not active but is primed to overheat when it is reactivated. The buttons for overheating the full mid and low racks have lit up because the pilot has overheated all the modules that can be overheated in these racks. The Damage Control in the second low slot is an example of a module which cannot be overheated. The red indicators between the capacitor and shield/armor/hull bars are the heat accumulated in the low/mid/high racks, and the red shown on the module icons is the overheat damage sustained by the module. (Note that, while this screenshot was taken in 2010, Overheat mechanics and their interface have not changed.)

The skill required to be able to overheat your modules is called Thermodynamics (3x, 4.5M ISK). This skill reduced the heat damage from overheating by 5% per skill level. This is a starting skill for characters made after the September 2015 Vanguard update, but before the September 2019 update. (Older and newer characters will need to train the requisites and this skill on their own.)

Support Skills

Additionally, Tactical Destroyers and Strategic Cruisers have skills which improve their ability to overheat modules.

  • (Racial) Tactical Destroyer - Provides 5% reduction to heat damage from overheating per level.
  • (Racial) Strategic Cruiser - Provides 5% reduction to heat damage from overheating, and 10% increase in damaged module repair amount per second, per level.
  • (Racial) Core Systems - Provides 5% reduction to heat damage from overheating per level, when the associated electronic warfare Subsystem is fitted.

Controlling Overheating

You can begin overheating a specific module by clicking the green light at the top of the module button. You can turn it off the same way -- note, though, that it won't turn on or off until the next cycle begins. Alternatively you can right click the module and choose to overheat it. You can also use a keyboard shortcut: by default you can overheat by holding down shift and pressing the key(s) required to activate a module normally. A module which has been set to overheat (or stop overheating) on its next cycle will have the green overheat light flash, until the new cycle begins and the overheat begins or ends. A module primed to overheat will stay primed after warping, but not after jumping or docking.

In some circumstances, you may need to overheat many modules as fast as possible. You can choose to overheat an entire rack (all the highslots, all the mid slots, or all the low slots) via the small buttons to the left of each rack.

The effects of overheating vary depending on the module. Most weapons will generate more damage (in the region of 15%). Tackling modules like webifiers get more range (about 20%). Propulsion devices like Afterburners boost your speed even more (roughly 50% more). With such benefits, it is easy to see that overheating is very powerful in the right circumstances.

There is also an option found by right-clicking the capacitor: "Lock Module Overheat State". When enabled, this blocks the ability to either overheat, or un-overheat (if they are already overheated), all modules. This can be used to prevent accidental overheating, however the inflexibility in it can just as easily cause other issues.

Not all modules can be overheated. For example, cloaking devices can't be overheated, and no passive modules can be overheated.

Red Giants

Wormhole space systems with the Red Giant effect have a significant impact on overheating modules. On the one hand, the system effect increases the magnitude of module overheat effects (listed below), however on the other hand, the system effect also increases the damage inflicted by modules when they overheat, reducing margin of error and causing modules to burn out faster. Overheating in Red Giant systems must be done much more selectively than in other regions of space.

Overheating Effects

Sortable by Module Type, Overheat Effect, and Percent Bonus
Module Type Overheat Effect Percent Bonus
Speed Bonus 50%
Warp Disruptor
Warp Scrambler
Range Bonus 20%
Stasis Webifier Range Bonus 30%
Stasis Grappler Optimal Range Bonus 300%
ECM Jammer
Burst Jammer
Tracking Distruptor
Guidance Distruptor
Remote Sensor Dampener
Target Painter
Strength Bonus 20%
Energy Neutralizer
Energy Nosferatu
Duration Bonus -15%
Armor Hardener
Shield Hardener
Strength Bonus 20%
Armor Repairer Duration Bonus
Strength Bonus
Shield Booster Duration Bonus
Strength Bonus
Hull Repairer Duration Bonus -15%
Remote Armor Repairer
Remote Shield Booster
Remote Cap Transmitter
Duration Bonus -15%
Remote Sensor Booster
Remote Tracking Computer
Strength Bonus 15%
Short Range Turrets Damage Bonus 15%
Long Range Turrets Duration Bonus -15%
Missile Launchers Duration Bonus -15%
Tracking Computer
Guidance Computer
Omnidirectional Tracking Link
Sensor Booster
Strength Bonus 15%
Cap Booster Duration Bonus -20%


  • Shield Boosters and Armor Repairers have multiple effects.
  • Weapon DPS bonuses aren't uniform: missile launchers and long-ranged turrets (artillery, beam lasers, railguns, and vorton projectors) fire faster, while short-ranged turrets (autocannons, pulse lasers, blasters, and disintegrators) get more raw damage-per-shot. Both ultimately result in more DPS, but it's worth noting that overheating won't give you a bigger alpha strike when you're using missiles or long-ranged turrets.


Modules that are overheated generate heat. This heat builds up in the ship (separated by module racks), and causes damage other modules in the same rack. Heat damage is what limits the use of overheating and has to be balanced between the need for the extra boost, and the risk of losing the module.

Rack Heat

Module heat damage is handled on a rack-by-rack basis, with the High Power, Mid Power, and Low Power modules each being handled independent of each other. As overheated modules cycle, they build up heat within their racks. The three segmented bars in the center HUD, between the capacitor and hitpoint bars, are the heat indicators for the racks (in order left-to-right of low|mid|high). Rack heat generation occurs continuously while modules are overheating, at a rate based on the number of modules being overheated, the type of those modules, and the size of the ship overheating them. Larger ships generate rack heat more slowly than smaller ships.

Module Type Rack Heat Generation/second
Afterburner, Microwarpdrive 4%
Most T2 modules 2%
All other non-T2 Modules 1%
Hull Size Rack Heat Generation Rate
Frigate, Interdictor, Command Destroyer[1] 100%
Destroyer, Tactical Destroyer 85%
Cruiser, Industrial, Mining Barge 75%
Battlecruiser 65%
Battleship 50%
Carrier, Force Auxiliary 40%
Dreadnought, Supercarrier, Orca, Rorqual 35%
Titan 25%
  1. ^ Most T2 ships have the same heat generation as their T1 variants. T2 Destroyers are the exception.

The values from these tables cannot be found in game. They must be found on outside sources. Module heat generation rates can be found on modules, under the attribute heatAbsorbtionRateModifier, and hull heat generation modifiers can be found on ship hulls, under the attribute heatGenerationModifier.

The time required for a rack to reach a certain heat level (starting from 0% rack heat) with a given set of overheated modules can be calculated with the following formula: H(t)=(heatCapacity/100)-e^(-t*heatGenerationMultiplier*sum(heatAbsorbtionRateModifier))

[math]\displaystyle \text{H(t)}= 1 - e ^ \left( \text{-t} \cdot \text{heatGenerationMultiplier} \cdot \text{sum} \left( \text{heatAbsorbtionRateModifier} \right) \right)[/math]

or, rearranged,

[math]\displaystyle \text{t} = \frac{-\ln{\left(1 - H(t) \right)}}{\text{heatGenerationMultiplier} \cdot \text{sum} \left( \text{heatAbsorbtionRateModifier} \right)} [/math]


  • H(t) is the target heat level, as a decimal (for example, 90% = 0.9)
  • t is the time in seconds
  • heatGenerationMultiplier is the "Rack Heat Generation Rate" from the above table based on hull size
  • sum(heatAbsorbtionRateModifier) is the sum of the "Rack Heat Generation/Second" (as a decimal) of all currently overheated modules in the rack

So for example, if a frigate overheating a Warp Scrambler I, it would take:

[math]\displaystyle \text{t} = \frac{-\ln{\left(1 - 0.5 \right)}}{1 \cdot \text{sum} \left( 0.01 \right)} = \frac{-\ln{0.5}}{0.01} = \frac{0.693}{0.01} = 69.3 [/math]

69.3 seconds to reach 50% rack heat, and

[math]\displaystyle \text{t} = \frac{-\ln{\left(1 - 0.9 \right)}}{1 \cdot \text{sum} \left( 0.01 \right)} = \frac{-\ln{0.1}}{0.01} = \frac{2.303}{0.01} = 230.3 [/math]

230.3 seconds to reach 90% rack heat

Meanwhile, if a Catalyst, with 8 Light Neutron Blaster II, were overheating its full gun rack, it would take:

[math]\displaystyle \text{t} = \frac{-\ln{\left(1 - 0.5 \right)}}{.85 \cdot \text{sum} \left( 0.02 \cdot 8 \right)} = \frac{-\ln{0.5}}{0.85 \cdot 0.16} = \frac{0.693}{0.136} = 5.1 [/math]

5.1 seconds to reach 50% rack heat, and

[math]\displaystyle \text{t} = \frac{-\ln{\left(1 - 0.9 \right)}}{.85 \cdot \text{sum} \left( 0.01 \cdot 8 \right)} = \frac{-\ln{0.1}}{0.85 \cdot 0.16} = \frac{2.303}{0.136} = 16.9 [/math]

16.9 seconds to reach 90% rack heat

This illustrates the speed at which large gun racks heat up and burn out, versus the much slower rate at which individual E-War or local repair modules will heat and burn.

The time required to increase rack heat from a given level to a target level is found by calculating the time required to reach the higher level, and subtracting the time required to reach the lower level. So, for that frigate to increase from 50% rack heat to 90% rack heat, it would take (230.3 - 69.3) = 161 seconds.

Rack Heat Dissipation

When no modules in a rack are being overheated, the rack will dissipate stored heat, at a rate proportional to how hot the rack is, via a very simple formula: Heat Dissipation per second = (Current Rack Heat %) * 1%. (For Example: at 60% rack heat, the rack will lose heat at 0.6%/second). However, Rack Heat is not immediately removed when a ship is docked or Repaired, it continues to dissipate at the normal rate; as a result, if a ship is docked to repair heat damage and immediately undocked, its racks may still have heat left in them even if its modules have been repaired.

The actual time required for a rack's heat to dissipate can be calculated using the following formula:

[math]\displaystyle \text{H(t)}= \text{H(0)} \cdot e ^ \left( \text{-t} \cdot \text{heatDissipationRate} \right)[/math]

or, rearranged,

[math]\displaystyle \text{t} = 100 \cdot \ln{\frac{\text{H(0)}}{\text{H(t)}}}[/math]


  • t is time in seconds
  • H(t) is the target heat level, as a decimal (for example, 90% = 0.9)
  • H(0) is the initial heat level
  • heatDissipationRate is 0.01 (on all ships)

So, for example, the time required for a ship to drop from 90% rack heat to 50% rack heat is equal to

[math]\displaystyle \text{t} = 100 \cdot \ln{\frac{0.9}{0.5}} = 100 \cdot 0.58778 = \text{58.8 seconds}[/math]

and the time required to drop from 50% rack heat to 20% rack heat is equal to

[math]\displaystyle \text{t} = 100 \cdot \ln{\frac{0.5}{0.2}} = 100 \cdot 0.91629 = \text{91.6 seconds}[/math]

The logarithmic nature of this formula implies that actually reaching 0% rack heat is impossible, so at some low value the server simply rounds down to 0%.

Module Heat Damage

Every time an overheated module's cycle ends, that module has a chance to deal Heat Damage (not to be confused with the Thermal Damage dealt by ship weapons) to itself and other modules on the same rack. The amount of damage a module will deal to other modules on an overheat cycle is visible in game in a module's Show Info window, under the name Heat damage. These values are generally higher for smaller-ship modules, lower for larger-ship modules, and somewhat proportionate to the modules' cycle times. (Faster-cycling modules generally have lower heat damage.) This Heat Damage value is the value which can be reduced by the skills listed at the top of this page. This is also the value which is increased by the negative system effect of Red Giant Wormhole systems. Modules will not always deal heat damage to themselves or others on every cycle ending, but when they do deal heat damage they will always deal exactly their listed amount of damage. Modules which have sustained heat damage will start to show red outlines around their icons in the hotbar (more red indicating more heat damage). The red outline will flash when a module sustains further heat damage from additional overheat cycles.

Module heat damage can be repaired in three ways:

  • Docking in a Starbase with a Repair Shop, or an Upwell Structure, and either bringing up the Repair Shop window from the starbase menu, or right-clicking on the damaged ship (or modules if they are unfitted) and selecting Get Repair Quote. Repairs in an NPC-owned station cost ISK.
  • Tethering to an Upwell Structure. While Tethered to an Upwell Structure, the Tether effect will repair module heat damage as well as the more visible shield/armor/hull/capacitor repairs it grants. However, this repair can be inconsistent at times, and either may not repair all damaged modules or may not repair them fully.
  • Consuming Nanite Repair Paste. Right-clicking the icon for a damaged, not-actively-cycling module in the hotbar will bring up a menu, containing the option Repair and a number in parentheses. That number is the amount of Nanite Repair Paste that will be consumed to perform the repairs. Selecting this option will begin to slowly repair the module (but will not immediately remove the Paste from cargohold) .
    • Paste used in repairs is removed from cargo when the repair completes. While a module is being repaired, the module cannot be activated, and no other modules on the ship can be overheated.
    • Repairs can be cancelled from the same right-click menu. Cancelling a repair before it is complete (including jumping a gate) will stop the repair at its current point, and remove repair paste from cargo based on how far the repair got. Jumping through a stargate will automatically cancel any repairs.
    • It is not possible to begin repairing a module if there is not enough paste in cargo to fully finish repairing it.
    • It is possible to repair a module while it is being Reloaded. This is a commonly recommended tactic for use on Ancillary repair modules and Rapid missile launchers: Overheat the modules while they are in use for their limited cycles, and then Repair the heat damage sustained during their long reload cycles.

Module Burnout

Every module has a certain amount of hitpoints (visible in its Show Info panel as Structure Hitpoints). In almost all cases, this value is 40HP, however for certain capital ship modules like Doomsday Weapons the value is in stead 99999HP or 999999HP (indicating that these modules effectively cannot be burned out by other modules' heat damage). If a module sustains heat damage exceeding its structure hitpoints, the module will 'burn out', and be forcibly set offline. A burned out module cannot be repaired with Nanite Repair Paste, and cannot be set online again or activated until it has been repaired. However, burned out modules are not destroyed or otherwise lost. Ideally, burned out modules should be repaired via a starbase or structure repair shop, however if a burned out module is partially repaired by being Tethered to an Upwell Structure, it can be brought online again while still in space. Burned out modules do not automatically re-online after being repaired; they must be manually reactivated.

Module Heat Damage Odds

As was mentioned, modules being overheated can, but may not always, deal heat damage to themselves and other modules. The odds of this happening is based on several factors:

  • The Rack Heat of the rack being overheated. As Rack Heat rises, the odds of heat damage instances occurring increases, and the odds of larger numbers of modules being damaged by one proc increases. In the past, this was erroneously believed to be a simple 1-4 multiplier on the number of modules that could be damaged at once, but in reality it acts as a percentage chance for a given module to receive heat damage, after the results of the other factors. (It is theoretically possible for every single module in a rack to be damaged by a single overheat cycle, however in practice this is highly unlikely.)
  • The placement of modules in the rack. Modules that are being overheated have the highest chance to deal heat damage instances to themselves and to immediately adjacent modules. Every additional module slot of distance away from an overheating module reduces the chances of that other module being damaged, to the point that modules on opposite ends of a rack have the lowest chances to damage each other. If a module is on the far end of a rack, or has only empty slots to one side of it, it may attempt to deal heat damage to the nonexistant modules off the end of the rack, which will result in the module itself erroneously flashing to indicate heat damage being dealt, and no heat damage actually being dealt in that direction. The result of this is that in a rack where only a small number of modules will be overheated, the best slots to place those modules is either on one far end (for one overheating module), opposite far ends (for two), or as evenly spaced across the rack as possible (for more); and the worst slots to place overheating modules in is either the center of the rack (causing it to damage all other modules in the rack) or adjacent to another to-be-overheated module (as they will damage and burn each other out). Note that these module placements apply to the fitting screen, not the hotbar; the placement of module buttons on the hotbar does not matter.
  • The number of Online, versus Offline or Empty, slots in the ship. The odds for any module to sustain overheat damage is based on the total number of Online modules on the ship, divided by the total number of high, mid, low, and rig slots on the ship. (Rigs do not count as online modules for this calculation.) This means that having one or more module slots on a ship empty, or one or more modules Offline, will reduce the chances of all modules on the ship sustaining heat damage. It also means that there is always a chance for an overheated module to not take damage on every heat cycle.
  • The ship, and the hidden heatAttenuation value for the rack. Every ship hull has three hidden attributes (named heatAttenuationHi, heatAttenuationLow, and heatAttenuationMid). In general, the values of these attributes correspond to the number of slots in the rack, with the numbers being higher for racks with more slots; however there are a small number of ships which have received balance changes to their slot counts but not had their attenuation values changed. Higher values of these attributes represent greater chances for heat damage to spread across adjacent modules down the rack. The value of the attribute is a decimal chance for the heat to spread to each further module, meaning that the chance for a given module to receive heat damage is equal to the heatAttenuation factor, raised to the power of the distance (in slots) between the overheated module and the module being damaged.

Heat Attenuation Values

In most cases, the number of slots in a rack directly corresponds to that rack's heatAttenuation attribute

Slot count heatAttenuation
1 0
2 0.25
3 0.5
4 0.63
5 0.707
6 0.758
7 0.794
8 0.82

The Master Overheat Damage Formula

The odds for a given module to sustain overheat damage on a single cycle can be condensed into one formula:

[math]\displaystyle \text{Damage Chance}= \text{Rack Heat} \cdot \left( \frac{\text{Online Hi+Mid+Low Modules}}{\text{Total High+Mid+Low+Rig Slots}} \right) \cdot \text{heatAttenuation}^\mathrm{Distance}[/math]

For example:

  • An Enyo (slots 5/3/4, 2 rigs), with 1 empty High slot, at 60% Rack Heat, overheating a Warp Scrambler in mid rack slot 1.

Odds of damaging the Warp Scrambler itself:

  • Damage Chance = 0.6 * [4+3+4 / 5+3+4+2] * [0.5 ^ 0]
  • Damage Chance = 0.6 * [11 / 14] * 1
  • Damage Chance = 0.6 * 0.786 * 1
  • Damage Chance = 0.471 = 47.1%

Odds of damaging the modules in slots 2 and 3:

  • Slot 2 = 0.6 * [4+3+4 / 5+3+4+2] * [0.5 ^ 1]
  • Slot 2 = 0.471 * 0.5
  • Slot 2 = 0.236 = 23.6%
  • Slot 3 = 0.6 * [4+3+4 / 5+3+4+2] * [0.5 ^ 2]
  • Slot 3 = 0.471 * 0.25
  • Slot 3 = 0.118 = 11.8%

Heat Sinking

Not to be confused with the module which increases Energy Turret damage, Heat Sinking is the commonly discussed practice of including either empty slots or unused modules to absorb heat damage in a rack and increase the lifespan of other modules in the rack. As has been demonstrated by the above section, this can be an effective and valuable strategy, including one or more empty slots or offline modules in a rack of otherwise hot modules. This is most commonly done in a ship's high slots, as mid and low slots are generally seen as far too valuable to sacrifice, but as has also been demonstrated, there are both correct and incorrect ways to heat sink a rack. The correct way to heat sink a rack of modules (usually weapons) is to spread the weapons as far apart and as evenly as possible, and then evenly intersperse a set of either Offline modules or Empty slots in between the guns. (Don't give up a Turret or Launcher Hardpoint just to get a better heat sink though. You still want to have the full set.) The incorrect way to heat sink a rack is either to leave all of the modules lined up next to each other (as the fitting system will usually do by default), or to evenly intersperse additional Online modules across the rack.

It is also possible in emergency combat situations to Offline non-essential modules in the heat of battle, to buy critical modules a little more overheat time. This is most commonly done with Microwarpdrives in fights with no way to escape a scram (however this is often more to remove the MWD's capacitor penalty than to use its slot for heating).

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