An analytical model of transient, simultaneous heat, water, and air transfer is developed in this paper. The resulting governing differential conservation equations are simplified by dimensional analysis and applied to a semi-infinite moist soil with an impermeable heat source at the boundary. Solutions for moisture and temperature distributions are generated numerically for varying surface heat flux and initial moisture content. Difficulties in using a moving boundary approach are discussed. The solutions predict, without using a moving boundary analysis, that a narrow zone with a steep moisture gradient moves through the soil at a rate such that the volume of soil dried per unit surface heat input is constant for a given initial moisture content.