Light Sources

How often do you think of the varied light sources in your home? The (almost) extinct A-Lamp incandescent (Figure A) has been replaced by innumerable options in the recent past, some of which are still emerging in the residential market. Below is brief outline of electric light sources, most of which you can find in your own home.

light bulbs


Vocabulary words

Kelvin – Measurement of light color ranging from 1500k (candlelight) to 6500k (daylight). Most residential light sources produce light between 2700k and 3500k at full intensity.

Lamp – Lighting industry term for a light bulb.

Luminaire – A complete light source including a lamp, together with the parts designed to distribute light and to connect the lamp to the power supply.

Incandescent – Light is produced when electricity is passed through a wire filament (Figure A). This creates a glow producing visible light (incandesces).  The most recognizable and easily interchangeable source of light available. It is very likely there will almost always be a replacement for our standard A-Lamp. Production has slowed recently due to their relative inefficiency.

Halogen – A type of incandescent (Figure B).  Halogen lamps emit brighter and whiter light than standard incandescent, and halogen bulbs are seen as a slightly more efficient option to traditional incandescent. Since halogen produces light at 3000k, we perceive a lower wattage to produce more light. Halogen is a dimmable source of light, but the increased energy efficiency is lost when halogen sources are dimmed. Until recently, halogen has been the main light source used to illuminate artwork because of its brilliance.

Fluorescent – Ideally, this source of light should be avoided at all costs (Figure C). The light emitted from a fluorescent source does not show color well and in institutional applications has been shown to negatively affect focus and overall well-being. These lamps are efficient, technically speaking: 25 watts of Fluorescent can produce as much light as 100 watts of incandescent, but the mercury vapor used to produce light is bad for the environment, specifically the ozone layer. The quality of fluorescent is much lower than incandescent. Fluorescent bulbs should be disposed of properly and replaced with the highly superior LED.

LED (light-emitting diode) – Vastly considered to be the premiere option for light sources (Figure D). With an average light of 50,000 hours, LED lamps are intended to last. When used residentially, an LED light bulb should only have to be replaced after 25 years of use. High quality LEDs are dimmable, and are used heavily in creating human-centric lighting systems. LEDs owe part of their durability to their construction: diodes are semi-conductors which require considerably less energy to operate.