Walking into an electrical store can be intimidating. At first glance all the lights are on, and the thousands of chandeliers and lamps are blinding. When you walk toward the lamps, you see shelves with dozens of options, shapes, colors, prices, and uses. In each package, informational tables with numbers that seem to make no sense at all. Lumens, color temperature, wattage. There are so many confusing terms. But before you give up on everything and rush back with the cheapest option, turning the lamp on only for it to make your house or the house you designed feel like a sinister back-country funeral home, some basic information can help you a lot. We know that good lighting design can greatly improve a building or even its occupant's productivity. And poorly designed lighting can ruin it or negatively affect its occupants. To help out, we've gathered some information that can help you the next time a light bulb burns out in your home.
Most common lamp types:
The most common type of lighting until recently, incandescent bulbs were the first models that made it possible to use electricity for light generation by heating a filament inside. Only about 5% of the electricity consumed is transformed into light. The rest turns to heat, which of course makes the device very inefficient. Because of this waste of energy, many countries have been banning the production and marketing of most incandescent light bulbs. Its characteristic light is soft, yellowish, and pleasing to the eye.
LED (Light Emitting Diode)
Currently the most common lighting type, LED's cover almost all lamp formats, functions, and types. The LED is a semiconductor diode composed of silicon and germanium crystals, which when energized emit light. They consume little electricity, generate almost no heat, and have a long service life. Variations include lamps, strips, and LED signs, which cover various color temperatures and lighting possibilities.
Fluorescent lamps are known for their efficiency, long service life, and low cost. They can be compact or tubular. They operate through a glass tube, internally coated with a phosphorus-based product. An electric current is conducted through the tube containing argon and mercury vapor, generating invisible ultraviolet light. The phosphor-based inner coating turns it into visible light. Because these lamps use heavy metals, such as mercury, they can never be disposed of in ordinary waste.
Halogens are incandescent light bulbs, but they use halogen gas to increase light emission and service life, increasing their efficiency and consuming less energy. However, because they still consume a lot of electricity in their operation, they have increasingly been replaced by LED lamps.
Color temperature is not the physical temperature of the lamp, but a parameter that determines, in scale, the "color tone" emitted by the lamps. The unit of measurement is Kelvin (K). The higher the scale, the colder the light. Incandescent lamps have a temperature of around 3500k (Kelvin), while fluorescent lamps are in the range of 6000k. Warmer lights make us more relaxed, while cool lights are typically more stimulating. In this previous article, we discuss the relationship between light temperature and mood. Blue lights can also have undesirable effects on our health, as we show in another article.
Luminous flux refers to the total amount of light emitted every second by a light source to produce a visual stimulus. Its unit is the lumen (lm). There are tables that indicate what the proper amount of lumens per square meter is for each environment. Generally this amount is given in lux (lx), which corresponds to a unit of luminance or illuminance, or the lumen of a surface for each square meter.
Wattage concerns the energy consumption of the lamp, measured in Watts (W), and has nothing to do with light emission. For example, a 60W incandescent bulb emits the same luminous flux as an 8W LED bulb or an 18W fluorescent one. However, there do exist products that indicate the efficiency or light output as expressed by the lumens / watt unit, which indicate how many lumens the lamp produces per watt of energy it consumes.
This is a metric that is not always apparent on packaging. But for architects, it can be quite important. As the name suggests, it is the opening angle of the light. There are lamps such as PAR 20 or dichroics that are made to illuminate specific elements, such as a painting. In these cases, they have smaller opening angles. Other lamps, which serve to illuminate larger spaces, should have much wider angles.