Ceramic materials are widely used in industrial high-temperature furnaces to influence thermal radiative heat-transfer. These materials have spectrally dependent (non-grey) emissivity behaviour. The combustion products of hydrocarbon fuels (mainly water vapour and carbon dioxide gases) are also present in many furnaces. These gases emit and absorb radiation in a number of discrete spectral bands of various strengths. This paper presents a theoretical investigation of the effect on fuel consumption of lining furnace surfaces with a range of different ceramic materials; the investigation uses the banded-zone method, and calculates the fuel input rates necessary to generate specified heat-transfer rates into the load. Some sample calculations are presented for a simple box furnace containing a cold and a hot load. These results show that permeable ceramics and ceramic coatings require a fuel input rate approximately 20% lower than that for ceramic fibres to achieve the same heat-transfer rate to the load.