Abstract: Combustion apparatus comprises a combustion chamber for effecting primary combustion of combustible material charged thereinto, an exhaust conduit for exhaust gases emitted by the primary combustion, primary air inlet means for directing primary air into said combustion chamber, and secondary air inlet means for directing secondary air into the exhaust conduit at least in the region adjacent the combustion chamber so as to promote further combustion of said exhaust gases, said secondary air inlet means including an air distributor arranged centrally of the conduit characterized in that secondary air inlets are additional provided in the wall of the conduit over at least part of the extent of the air distributor.