Hearths

Overview
Hearths are the heart of the settlement. Every settlement starts with an Ancient Hearth and can construct other  Small Hearths from the City Buildings menu. Hearths are buildings with Specialization that employ a single  Firekeeper to keep the Hearth lit by burning  fuel. Fuel can also be Sacrificed in the Ancient Hearth. Every villager takes their breaks at the nearest Hearth to warm themselves, eat, and fulfill their needs. By upgrading the Hearth with decorations, housing, and Service buildings, you can unlock up to 3 tiers of stackable benefits. The Ancient Hearth can get corrupted at Veteran Difficulty and higher.

Hearth Types
The heart of the colony is protected by the Holy Flame. Villagers gather here to rest, eat, and receive clothing. If the fire goes out, people will lose hope. No Hope Resolve effect: -20 Resolve.
 * Ancient Hearths :

Small Hearths cannot be built too close to the Ancient Hearth or to each other - the ranges of your Hearths (approx. radius of 9 squares) may never overlap.
 * Small Hearths :

Small Hearths are identical to Ancient Hearths, except you do not receive a Firekeeper bonus and you cannot  Sacrifice fuel. It is OK if Small Hearths go out, but villagers will be unable to rest or fulfill their needs at an unlit Hearth and will instead travel to the nearest available lit Hearth.

Fuel
There are 4 fuels that can be burned in Hearths:, , , and.

You can decide which type of fuel will be burned in each Hearth using the checkboxes next to the fuel types in the Allowed Fuel menu. All Hearths share this setting. If you have multiple fuels selected, the leftmost one will always burn first. There are also options in the settings that allow you to customize which fuels are automatically enabled when starting a new settlement.

Firekeeper bonus
Every settlement starts with an Ancient Hearth which must always remain lit. If the fire goes out, all villagers will lose 20 Resolve. To keep the flame burning, a Firekeeper and a steady supply of fuel is needed. Your choice of Firekeeper in the Ancient Hearth will grant your settlement a species-specific bonus. Small Hearth Firekeepers don't provide any bonuses.

Villager Breaks

 * Main article: Breaks

Every few minutes villagers have to return to a nearby Hearth for a break, to eat, rest, and satisfy needs. All consumption happens during breaks. Villagers of different species take breaks at different Intervals.

Hearth upgrades
Level 1 Hearth upgrade is available from the start. Upgrading to level 2 and 3 requires you to unlock levels 2 and 4 of the Brass Forge respectively.

Click on the Hearth to see what is required to upgrade. As seen on the image on the right in the Upgrade Requirements section, we still need 4 Comfort Decorations and 4 Aesthetics Decorations before the Hearth upgrades to level 2.


 * Housing, Decorations, and Service buildings need to be placed fully within the Hearth Radius for them to count towards upgrades.
 * The Hearth upgrades itself automatically once all the requirements are fulfilled.
 * Both Ancient and Small Hearths can be upgraded.

Sacrificing
Fuel can be sacrificed in Ancient Hearths to temporarily gain powerful positive effects. Sacrificing is extremely resource intensive and requires significant labor investment, or even restructuring of the whole settlement, should you wish you keep it up for an extended period.

You can Sacrifice up to 3 stacks of, , , or. Each fuel's Sacrificing stacks are independent. To choose how many stacks you want to Sacrifice, use the green arrows next to the fuel type. Activating Sacrifice immediately consumes 1 unit of fuel, even if you are paused. If you only have 1 unit of this fuel to begin with, you will keep the effect for as long as you are paused. If you don't have any fuel of one type, its green arrow is going to appear grayed out. Do not forget to reset the stacks to 0 once the need for Sacrifice has passed - you will quickly run out of fuel otherwise. There's also a checkbox to Stop after storm.

There are 3 visual indicators of Sacrificing taking place:
 * An orange aura around the Ancient Hearth.
 * An Perk in a gray outline with the number of stacks in the Perk section on the bottom left of the screen.
 * An exclamation mark in a yellow diamond next to the fuel Resource Category in the upper section of the UI. It says "You are sacrificing fuel in the Hearth." if you hover over it.

Each fuel type grants different boons:

There are 2 modifiers that affect Sacrificing efficiency, outside of Cornerstones:
 * Sacrificial Flame: resources sacrificed in the Ancient Hearth burn 10% longer. A Monastery of the Vigilant Flame level 7 upgrade.
 * Prestige 18: the Ancient Hearth seems to have a defect. No matter how hard the firekeeper tries, sacrificed resources are burning 35% quicker.

The table below shows how much fuel you need to Sacrifice per stack to keep the effects, depending on your upgrades and Difficulty:

Corruption

 * See also: Blightrot

Blightrot infects Hearths. The more Blightrot Cysts a Viceroy generates from Rain Engine use or Glade Events, the faster their Hearths get corrupted during Storm Season, when Blightrot Cysts open up. Once the Ancient Hearth reaches the Corruption limit, it triggers Voice of the Sealed Ones. Voice of the Sealed Ones sends out 3 ghosts from the Ancient Hearth that seek out and kill 3 random villagers. As soon as the Hearth discharges, Corruption is reset to 0 and starts rising again.

Lowering Corruption
The only way to lower Corruption during Storm is to employ the help of Blightfighers in a Blight Post. Blightfighters search for Cysts and burn them with. Every Cyst burned lowers Corruption by 50. Once all Cysts have been burned, any new ones will not open up till next Storm Season. Any Cysts left close and Corruption resets to 0 as soon as the year ticks over and Drizzle Season starts.

Corruption Resistance and Corruption rate
Corruption Resistance is a measure of how high the Corruption limit is. The higher the Corruption Resistance, the more time it will take for Voice of the Sealed Ones to activate. An Ancient Hearth that hasn't been  upgraded has 1000 Corruption Resistance. Every Ancient and Small Hearth level raises Corruption Resistance by 150. It can also be raised with different Effects.

The Corruption rate per Cyst is 60 Corruption/minute up to Prestige 10, and 90 Corruption/minute from Prestige 11 onwards.

Assuming a Hearth upgraded to level 2, you will reach the Corruption limit of 1300 at least once without burning any Cysts:
 * At 60 Corruption/minute in a 2-minute Storm with 11 Cysts.
 * At 60 Corruption/minute in a 4-minute Storm with 6 Cysts.
 * At 90 Corruption/minute in a 4-minute Storm with 4 Cysts.

Hearth Tips

 * Use as Hearthkeepers when you are running low on fuel and, especially on Marshlands and the Sealed Forest.
 * are nifty as Hearthkeepers before and after Glade Events to carry goods to and from these Events.
 * are excellent during the Storm Season as Hearthkeepers to keep Hostility down and stop Forest Mysteries from triggering.
 * are invaluable when playing World Modifiers like Land of Greed to slow down the Queen's Impatience.
 * as Hearthkeepers will help you in achieving Resolve - based Orders.
 * Since Firekeepers in Small Hearths don't offer a species-specific bonus like they do in the  Ancient Hearth, you can take advantage of its  specialization synergy with Lizards.