Hot wet air in bathrooms contain considerable amounts of thermal energy when we take a bath. Heat recovery ventilators could be an option to recover the waste heat in bathroom and create a better indoor environment. This study reports a novel bathroom straw heat exchanger (BSHE) unit which consisted of flexible plastic straws, PVC pipes and bathroom extractor fans. During its operation, the indoor exhausted hot air would be recovered through a cross flow pattern. The prototype was built and tested under laboratory conditions, exploring its sensible effectiveness and sensible recovered energy. The results showed that the BSHE unit could help to take advantage of waste thermal energy in bathrooms. The unit had advantages of low cost, easy installation and being energy-saving. However, investigations on latent energy effectiveness and different heat exchanger material choices for BSHE unit should be conducted, as well as real-life operation.