Water table depth data for use in modelling residential building ground-coupled heat transfer

Abstract

Water table depth influences ground-coupled heat transfer through the foundation of residential buildings and impacts energy consumption required for heating and cooling. Knowledge of water table depth in Australia is required to determine the extent of this impact on Australian housing. This study conducts a review of water table depth data in Australia and presents a case study indicating that 46% of Victoria’s Urban Growth Zone has water table depths estimated to be less than 5 ​metres. Houses built here with no insulation to the slab and on average soil type would have a 24%–54% higher heat loss than if there was no water table. The degree of impact varies with changing water table depth in different locations and over time. The uncertainty associated with estimated water table depth is large. Extending residential energy rating tools to account for water table depth would require the development of Australia-wide water table depth data.