The application of thermo-active foundation (TAF) systems to heat and cool residential buildings is evaluated in this paper. First, a transient three-dimensional finite difference numerical model is developed for the analysis of thermo-active foundations. The numerical model predictions are then validated against experimental data obtained from laboratory testing. Using the validated numerical model, G-functions for TAFs are generated and integrated into whole-building simulation analysis program, energyplus. A comparative analysis is carried out to evaluate TAF systems compared to conventional ground-source heat pumps (GSHPs) to provide heating and cooling for multifamily residential buildings. In particular, the analysis compares the cost-effectiveness of TAFs and GSHPs to meet heating and cooling needs for a prototypical multifamily building in three U.S. climates. Due to lower initial costs associated to the reduced excavation costs, it is found that TAFs offer a more cost-effectiveness than GSHP systems to heat and cool multifamily residential buildings.