In the practical applications, roofs of buildings can be in different shapes depending onarchitectural design of building or climate. Some of these building roofs can be classified asgambrel, saltbox and gable roofs. In the present study, we investigated the natural convectionheat transfer and fluid flow inside the gambrel, gable and saltbox roofs for winter boundaryconditions. With this aim, the identified roofs are compared with each other from the heattransfer and flow field point of view. Effects of Rayleigh number also tested in each type.Results are presented with streamlines, isotherms, local and mean Nusselt numbers. It isaimed that this study will help for designer to show more efficient ways of saving energy.