Fundamental concepts of interior design include understanding how to utilize space in a way that is both pleasing to the eye and functional for the people who will be using the space. In order to do this, interior designers need to have a basic understanding of architecture, engineering, and psychology. They must also be familiar with principles of design such as balance, proportion, rhythm, contrast, and harmony.

Interior designers should know how to utilize space in a house in order to make the most of the available area. They should consider the needs of the occupants and design accordingly. Additionally, they should be aware of the various architectural features of a house and how to best use them to enhance the interior design.