In recent years there has been significant progress in fabrication of low bandgap thermophotovoltaic (TPV) devices, such as InGaAsSb, InGaAs and GaSb cells. However, only limited data are available in the literature with respect to the performance of these TPV cells in combustion-driven radiant sources. In this study, power generation using InGaAsSb TPV cells has been investigated in a gas-fired home heating furnace. The radiant power density and radiant efficiency of a gas-heated radiator were determined at different degrees of exhaust heat recuperation. Heat recuperation is shown to have a certain effect on combustion operation and radiant power output. The electric output characteristics of the InGaAsSb TPV devices were investigated under various operating conditions. An electric power density of 5.4 x 10(3) W m(-2) was produced at a radiator temperature of 1463 K for the small cogeneration system. The cell short circuit density was observed to be greater than 1 x 10(4) A m(-2) at a radiator temperature of 1203 K. Furthermore, the design aspects of combustion-driven TPV systems have been discussed. It is shown that development of a special combustion device with high conversion level of fuel chemical energy to useful radiant energy is required, to improve further the system efficiency. (C) 2003 Elsevier Ltd. All rights reserved.