Interior design is a practice concerned with anything that is found inside a space - walls, windows, doors, finishes, textures, light, furnishings and furniture. All of these elements are used by interior designers to develop a functional, safe, and aesthetically pleasing space for a building's users.

The work of a interior designer draws upon many disciplines including environmental psychology, architecture, product design, and traditional decoration (aesthetics and cosmetics). They plan the spaces of almost every type of building including: hotels, corporate spaces, schools, hospitals, private residences, shopping malls, restaurants, theaters, and airport terminals. Today, interior designers must be attuned to architectural detailing including: floor plans, home renovations, and construction codes.

Although the terms interior design and interior decorating are sometimes used interchangeably, each discipline exhibits a distinct difference in its scope. Interior design involves manipulating the architectural integrity of the interior space. Interior decorating, on the other hand, is generally focused on the selection and presentation of interior items within a space, such as furniture, accessories, finishes and room layout.

Size of the industry

The industry revenue in the United States for interior design was $11,108.4 million in 2007 with a revenue growth of .5%. That same year, there was around 84,018 establishments and 72,377 enterprises recorded.

Specializations

Interior designers can specialize in a particular interior design discipline, such as residential and commercial design, they can also help with making rooms in the hospital and even work with schools to make offices or another things with some developing expertise within a niche design area such as hospitality, health care and institutional design. In jurisdictions where the profession is regulated by the government, designers must meet broad qualifications and show competency in the entire scope of the profession, not only in a specialty. Designers may elect to obtain specialist certification offered by private organizations. Interior designers who also possess environmental expertise in design solutions for sustainable construction can receive accreditation in this area by taking the Leadership in Energy and Environmental Design (LEED) examination.

The specialty areas that involve interior designers are limited only by the imagination and are continually growing and changing. With the increase in the aging population, an increased focus has been placed on developing solutions to improve the living environment of the elderly population, which takes into account health and accessibility issues that can affect the design. Awareness of the ability of interior spaces to create positive changes in people's lives is increasing, so interior design is also becoming relevant to this type of advocacy.