exhaust manifolds 134 through the other side of the heat exchanger wheel 122 and through the exhaust fan 138 the draw for the exhaust gases is provided by the exhaust fan 138 the ceramic heat exchanger wheel 122 is of the same nature as the heat exchanger wheel 34 of fig1 and the heat exchanger wheel 80 of fig2 in this embodiment the gas burners 108 are alternated with the turbulating air pipes 110 the turbulating air pipes increase the heat transfer of the gases and significantly increase the efficiency of the furnace in addition the heat exchange between the exhaust gases and the combustion and turbulating gases reduces the energy requirements of the furnace and makes the furnace significantly more efficient the combination of the heat exchanger and the turbulating gases has been found to increase the efficiency of a furnace of this nature to about 60 from at best about 20 the ceramic heat exchanger wheel makes the heat exchange possible and effective because of a low air loss across the thermally stable gap seal the low pressure loss eliminates the need for the hot air fan or larger combustion blowers so that sufficient air is supplied to the burners and turbulating air pipes 110 further the heating of combustion gas greatly reduces the fuel requirements because the combustion gas does not have to be brought up to combustion temperature normally the combustion gas must.