© 2021 Elsevier B.V.Energy and water are two critical resources, and their security has been becoming a regional, national and global priority. The paper investigates the energy-water nexus at the building level through developing a novel energy-water ratio and a thermal model, to provide insight about the interaction mechanism between energy and water at the building level. The developed energy-water ratio has clear physical meaning. The thermal model developed can be used to explore the dynamic interdependences and feedback mechanism between energy and water, and to evaluate the value of interdependence and the real value of infrastructure through linking to business model. The dynamic of energy-water nexus for three kinds of buildings in London is then examined under present and future climate scenarios. Results show that the interdependences of energy-water for these three kinds of buildings vary over time and are different each other. The different interdependences are shaped by the combined effect of both the configurations of infrastructures for building and the environmental condition. The improved energy efficiency of boiler can save not only energy but also water, indicating the positive interaction between energy and water. Results have informative implications for sustainable building and investment in household infrastructures, and suggest an integrated way for co-managing both energy and water effectively.