Heat storage is a phenomenon known from the large mass stoves where heat is stored in the stones surrounding the combustion chamber.
Heat storage in a wood-burning stove is the combination of the wood-burning stove's ability to quickly and comfortably distribute the convection heat and the mass stove's ability to store the heat.
The compartment can be filled with a large amount of stone. Stone has a special ability to store heat from the wood-burning stove, which will then slowly be emitted into the room, even long after the fire has died.
While the wood-burning stove is burning, the stone in the heat storage compartment will be heated up. Once the fire in the combustion chamber has died, the stone will continue emitting the stored heat into the room.
Tests show that stone in the small heat storage compartment will keep warm for up to 10 hours, whereas stone in the large storage compartment will keep warm for up to 14 hours after the last stoking.
As an extra feature, the HWAM 3500 Series, HWAM 7100 series and HWAM 3650 and HWAM 3660 have a knob which regulates the convection air to the heat storage compartment. When the convection damper is closed, the heat stored in the stone will be retained in the heat storage compartment for as long as possible; once the damper is opened, the heat will be distributed to the room as quickly as possible.