This paper presents a theoretical and experimental study of a novel water heat exchanger that heats the air in a domestic clothes tumbler dryer in place of a traditional electric heater, with a view to improve its energy efficiency. Modelling of a waste heat recovery heat exchanger has been undertaken using EES software package to assess its effectiveness on the drying cycle. The new dryer was found to have shorter drying times, better moisture extraction rates for the same power input and hence more efficient than the traditional dryer. (C) 2009 Elsevier Ltd. All rights reserved.