The architecture of light: architectural lighting design concepts and techniques. A textbook of procedures and practices for the architect, interior designer and lighting designer pdfdrive com

The Properties of Incandescent Sources:
Initial Cost: cheap!
…Dirt cheap. This is the primary reason incandescent sources are so common. The small price tag compels us to reach for incandescent lamps despite our knowledge or their inefficiency and short lamp life.
Operating Cost: Expensive;
Incandescent sources are inefficient and short-lived. They convert
only about 1/3rd of the quantity of input electricity into visible light. The remaining 2/3rds leaves as heat. Incandescent sources are expensive to electrify and require frequent, costly, labor-intensive relamping.
Color Rendering Index: 100 (great);
The filament of the incandescent source is engineered to incandesce in a manner that delivers every wavelength of visible radiation. This complete output spectrum can reveal all of the colors that the surfaces in an environment have to offer. This desirable color- rendering ability is another reason we are so reluctant to move away from these sources.
Color Temperature: warm;
Incandescent sources actually operate at the temperature that corresponds to their color temperature. Standard incandescent filaments are heated to about 2800 degrees Kelvin, so the warm, yellow-orange light given off by the source can be described as 2800 Kelvins. This warmth is another reason we seem to be attracted to these sources. The warm color temperature translates well in intimate, relaxed environments.
Ballast and Transformer requirements: None;
Incandescent sources require no special components to operate. Line voltage electricity is simply driven through the filament, which heats to a point of incandescing.
Dimming: Cheap and Easy;
Incandescent sources can be dimmed simply by lowering the amperage (quantity) of electricity that is pushed through them. This can be accomplished with a simple wall box dimmer that can be installed in place of most common light switches.