We've completely redesigned the burn chamber to increase airflow and heat output:
Once you light your fuel, the fire burns sideways because of drafted air. This air hits the back of the stove, creating turbulence - and thus a secondary burn. Because of the bottom chamber, pre-heated air combines with the secondary burn to create a super-hot fire.
The Hot Ash Stoves have been designed to conveniently nest to make pack-up simple and easy.