Whether you work in the electrical field, or are an at home do-it-yourselfer,
it is a good idea to familiarize yourself with different types of lighting. If you are looking to light up a large area, your choices are pretty much limited to HID or LED lighting. In this article, we will explore the differences between the two types of lighting and see which one might be the best choice for certain applications.
Let’s first look at how HID lighting works. Whereas most light bulbs have a filament, HID light bulbs have a capsule of gas. The light comes from an arc discharge between two closely spaced electrodes. The discharge is sealed inside a small glass tubular capsule. HID light also requires a ballast that regulates the voltage supplied to the capsule of gas. The light produced is greater than most standard light bulbs and also produces a quality of light that can better replicate that of natural daylight.
The light in an HID bulb is produced by passing a current through metal vapor. Free electrons collide with an atom in the vapor knocking an electron into the higher orbit of the atom. When the electron falls back to its lower orbit, radiation is released. The wavelength of the radiation will vary depending on the energy zone of the electron and the type of metal vapor used in the tube arc.
LED lights work by utilizing diodes that give off light when they are connected to a circuit. LEDs then produce a form of electroluminescence as a large number of photons are released outward. The LED is contained in a plastic bulb that concentrates the light source.
An essential part of the LED light is a semi-conductor chip that is located in the light source. The chip has two regions that are separated by a junction. These include the p region which is dominated by a positive charge, and the n region, which is dominated by a negative charge. When enough voltage is applied to the semi conductor chip, the electrons cross the junction into the p region.
When an electron moves close enough to the positive charge in the p region, the two charges combine again. When this happens, electric potential energy is converted to electromagnetic energy which causes a quantum of electromagnetic energy to be released in the form of a photon of light. The photon has a frequency which may vary according to the characteristics of the semiconductor material. The colors the LED light emits depends on these semiconductor materials.
To think of it in more simple terms, LEDs are like tiny bulbs in an electric circuit. However, they do not have a filament. Their illumination is caused by the movement of electrons in a semiconductor material.
HID Lighting Uses
HID lighting is typically used to light up large spaces. Here are some examples of where they might come in handy:
Stadiums: Not only do HID lights light up these vast spaces adequately, they provide that daytime lighting that makes it appear as if games are being played in the middle of the afternoon.
Parking Garages: Another vast location which benefits from the safety of a strong HID light.
Retail Stores: The bright lighting provided by an HID light can be beneficial in stores, making products look attractive.
Street Lights: HID lighting was originally made for the purpose of supplying light for streets. Originally these lights were mercury vapor but they have been largely replaced by metal halide and high-pressure sodium lamps.
LED Lighting Uses:
LED lights can be used for a variety of things that can include Christmas lights, stage lights, accent lights, home and business lights and lights for boats and automobiles. As for the applications that HID lights are used for, yes, they can cover that as well.
LED vs. HID Lights: A Comparison
So, let’s look at the characteristics one might look for in lighting and see which kind of light comes out ahead.
Energy Efficiency: Both LED and HID lights offer 100+ Lumens/ Watts. In the case of the HID lighting, consumers should be aware that certain factors can reduce a lamp’s efficiency. In the case of LEDs, technology is constantly being updated to increase energy efficiency.
Durability: HIDs are fragile due to their moving parts, glass bulbs and filaments. LEDs are heavy duty due to the fact that they have no electrode or filament and they are shock and vibration resistant.
Lifetime: HIDs offer a lifetime of 15,000 to 35,000 hours while LEDs offer 50,000 hours plus.
Lumen Depreciation: For HID lights, lumen depreciation is moderately high. LEDs tend to last longer but light output will decrease over time. The rated life reflects when LEDs can lose 30% of its light.
Cold Tolerant: Here HIDs win out, withstanding temperatures of up to -40 F while LEDs will withstand up to -30 F.
Performance: HID’s typically take 5-10 minutes to warm up and then creates light in all directions. LEDs power on instantly and can create both focused and omni-directional light.
Color Temperatures: This will control the tone of the light you are seeing. For HID lights, there are less options as the color temperatures range only from 3000 to 5000 Kelvin whereas LED offer options ranging from 2700 to 6500 Kelvin.
Color Rendering: This will determine how accurate the color of the light will appear once lit, with 100 being a perfect rendering. HID light’s color rendering can vary wildly with CRI’s ranging from 5 to 93 while LEDs range from 80 to 95.
Dimmable: HID lights are not dimmable whereas most LED lights are.
Warranty: An HID light will typically have a warranty of 1 to 2 years while an LED usually offers a 5-year warranty.
Cost: Here the HID lights win out offering a lower up-front cost. However, these savings could be countered by maintenance costs that can arise down the road. LED lights have a higher up-front cost but virtually no maintenance.
After reading all these points of comparison, it’s hard to imagine why anyone would choose HID over LED lighting. However, HIDs might make sense to someone who is looking for temporary low-cost lighting. It also is a good choice for those looking for lighting that will hold up in extreme temperatures or to match existing ballasts for HID lighting fixtures that are still in good shape.
So, we can see how LED lighting and HID lighting works. We can also compare to HID lighting for the illumination of larger areas. No matter what decision you make, it’s a good idea to know about HID and LED lighting so you can see which option works best for you.