The Hearth is the Dwarven equivalent of the Well of Men, healing wounded troops and replenishing battalion numbers. It addition to regular build plots, it can also be constructed on the two special build plots near the citadel unlocked through research at a level 3 Stonemason (Line of Defense). Furthermore, a Battlewagon can be upgraded with a Hearth to heal nearby allies out on the battlefield.
Hearth - The Hearth serves to heal heroes and allied battalions.
Hearths can be used to support armies that are heavily defending their base, allowing them to last longer in battle. They can also be combined with a tower and a heroic statue on generic outposts to provide a forward base where attacking forces can recover.