the most realistic theory about the fuel of the garmkhaneh is that there was an underground ceramic piping system between the public toilet of the jameh mosque and the hammam and probably gases like methane and sulfur oxides led to the torch of heated pool by the natural suction method and methane and sulfur oxides burned directly as the heating source in torch, or these gases were used from the wastes of hammam. according to old residents in the neighborhood, there was an artificial marsh behind the garmkhaneh and wastewater flew in the marsh and needed gas was obtained from this marsh.