Our objective is to understand attic space thermal behaviorusing computational fluid dynamics (CFD). Extensive modelingand CFD simulations have been used to predict the temperature,airflow, and air velocity of unconditioned attic spacesunder building cooling and heating and outside weather conditions.The two-dimensional natural convection in isoscelestriangular enclosure is investigated for laminar and turbulentflows. The base and inclined walls are kept at constant temperatures.The enclosure is assumed to be filled with viscous,incompressible Newtonian fluid.A comprehensive parametricstudy has been conducted to study the effect of different parameters,such as the Rayleigh number, attic geometry, and the atticangle on the thermal characteristics of the attic.