Abstract: A vertical chamber for waste disposal and heating purposes has an upright combustion chamber with an inlet for waste material, a grating at a lower chamber end and an adjustable burner controlled by a temperature sensor so that the burner operation can be adapted to allow for the calorific value or requirement of the material to be incinerated. A trap door is situated at the lower end for ash removal and is arranged by air passages to permit air to pass upward past the door for combustion and to open periodically for removing ash. The grating may be water cooled and step down towards the trap door to permit ash to be blown off onto the door before the door is opened.