HID refers to a class of gas discharge lamps including high pressure and low pressure sodium (HPS), mercury vapor (MV) and metal halide (MH). Before the invention of LED lamps, HID lamps have always been the dominant position of Plant lighting.
1. Light effect (lumens per watt)
Compared with other types of traditional artificial lighting, today's double-ended HPS lamps are quite efficient, producing more than 100 lumens per watt. The light output of the LED light laboratory has exceeded 300 lumens per watt. With the advancement of technology, the efficiency of LEDs continues to increase, and the cost per lumen output is also falling.
2. Reflection efficiency
HID lamp is a diffuse light source, it needs a reflector fixture, the reflectivity of the best reflective material used in the fixture is about 95 percent , it usually may have a lot of reflection, so even the best HID lamp, its overall lamp The efficiency is usually only 85 percent or lower. Since LEDs are directional, there is no reflection loss.
3. Lamp degradation and spectral instability
After one-year operation, the output power of HID lamps may be reduced by 10-15 percent . In the case of HPS, when they degrade, the spectrum shifts to the green/yellow range, which is the worst range of the spectrum. Plant utilization. Therefore, most professional growers replace HID lights at least once a year. The rated life of the LED lamp is at least 50,000 hours, the output power drops by less than 10 percent , and it will usually continue to work beyond its rated value with almost no change in the spectrum.
4. Cooling requirements.
The inner wall temperature of HID lamps is about 400 degrees Celsius, so if cooling is not used, they may become a potential fire hazard. About 75 percent of all energy consumed by HID lamps is emitted in the form of heat, and most of the heat is in the form of infrared (IR) radiation. Therefore, not only does the HID system require a lot of air conditioning, but the high level of IR can heat the blades without increasing the air temperature. Compared with HID, LEDs usually generate 50 percent less heat, and most of the heat from the LEDs is generated from the back of the circuit board and transferred to the heat sink instead of being radiated to vegetation.
5. Fixed spectrum output of HID
LED is the only-lighting technology that can be designed to meet the specific spectrum of plants. A single LED chip produces a very narrow spectrum band, so LED growth lights can be precisely mixed to provide an optimized spectrum to maximize the absorption and utilization of plants.
6. LED is safe, simple and easy to use
Compared with the non-ventilated HID system, LED does not need to replace the lamps, and the cooling requirement is reduced by 40-50 percent . They will never cause a fire hazard in the close range of a growing tent, and they produce almost no layered infrared (IR) radiation.
It is for these reasons that LED grow lights have become the first choice to replace HID as garden lighting.
