The Interzone Temperature Profile Estimation (or ITPE) technique is applied to determine the steady-periodic temperature distribution within earth in contact with a partially insulated rectangular basement. A water table is assumed to exist at a given depth below the soil surface. The solution derived addresses all the common insulation configurations for basements and crawl spaces. The effect of basement depth and of partial insulation length and U-value on the mean, amplitude. and phase lag of total heat loss from the basement floor and walls is investigated through a parametric analysis.