Heat essentially limits the amount of intensive activities a ship can perform in a given period of time. The amount of heat that a ship currently has is displayed in the Heat Indicator. Each module has a percent of Power usage (can be seen in the Modules sub-panel on the right) which indicates relatively how much heat it will generate when it is being utilized. Each activity that is performed (boosting, shooting etc.) as well as being in certain environments (close proximity to a star) will increase the heat in a ship. Once the heat is greater than 150% the ship's hull will begin to take consistent damage.
Ships are standard equipped with heat vents that collect heat and transport it out into space. To improve cooling of a ship, the player can equip Heat Sink Launchers. This allows the player to instantly dissipate some of the ship's built-up heat, or by upgrading the ship's Power Plant, which will not overheat as quickly.
A higher amount of heat will also increase the ship's Signature which means that the ship will be more easily detectable by other ships in the area. If a ship has no heat (generally because modules have been turned off or it is in Silent Running mode, trapping all heat inside the ship), then it will be nearly undetectable by other ships unless they are close enough to see the ship visually.
Heat will damage modules when the ship's internal temperature exceeds 100%. When heat remains above this value, modules may randomly suffer small amounts of damage every few seconds. Should the ship's heat rise above 160% then the ship’s hull will start to lose integrity.
Be aware, when your WEP capacitor is low, more heat will dissipate out from the weapon’s cooling loop and increase your ship’s temperature.