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

Ballast, Transformer and Driver Requirements: Many sources rely on specialized electronic or magnetic equipment to convert standard line voltage electricity to something more suitable for the source. These devices are often built integral to the lamp, integral to the luminaire, or are remotely mounted within a specific distance of the source. Often they must be installed such that they are accessible for maintenance or replacement.
Dimming: Many sources can be simply dimmed. Others require a careful matching of dimming controllers specific to the source type. Some electric light sources cannot be dimmed at all.
Instant on / off: Many sources require time to “warm-up” to present full light output. Some sources, when turned off, must be left off for a “re- strike” time period before they can again be switched on.
“Directability”: An indication of how focused the light leaves the source. Some lamps have optical reflectors built into them. Other sources rely on luminaires to optically control and direct light. The ability to focus light from a source is related to the size of the source. The smaller the light source, the easier to harness, control and direct it.
Efficacy: A fancy word for efficiency; this is an indication of how well the technology converts electricity to visible light. Most electricity “wasted” in an electric light source is converted to heat, which must be considered in its own right. Efficacy is expressed as lumens of light “out” for watts of electricity “in” or simply “lumens per watt”
Lamp Life: indicates how long a light source provides a working percentage of its initial light output. This is helpful for selecting and planning as the labor to replace a lamp is often more costly than the lamp itself. It is good practice to replace lamps in bulk before they actually fail. Lamp life is commonly expressed in thousands of hours. A common assumption is that 1000 hours translates to roughly 1 year of typical use residentially and 3000 hours translates to a year of commercial use.
These assumptions assume about three hours or nine hours of use per day
(respectively). Adjustments should be made accordingly.