North windows never experience direct sunlight so they do not require shading devices or tint. South-facing windows experience considerable direct sunlight in the winter months when the sun is lower in the sky. This can be beneficial if the solar heat can aid in warming the house in the cooler months. However, in the summer, the overhanging roof eaves can largely shade south windows. Observe south windows carefully to determine their need for tint or shading devices.
Windows facing east or west are the main source of intrusive heat.
Without shade or tint, these east or west windows can admit significant heat to the interior of a building since they experience many hours of direct sunlight daily. Shading devices or tint is definitely recommended for these windows. If exterior-shading devices cannot be installed, window or glass treatment should be considered. Treatments can be either heat reflecting glass or heat reflecting coatings. So, in most cases if glass treatment is to be added to an existing building, tinted film is applied.