Common type industrial lighting sources introduce 

High intensity discharge (HID) is a big family of lighting including metal halide (MH) and high pressure sodium (HPS). They have different applications. For instance, 400 watt or 1000 watt metal halide flood light is applied for outdoor high-mast sports field, high-bay warehouse, factory, gym, while 250W, 500W or 1500W high pressure sodium lamps are suitable for grow light, street, sidewalk and highway lighting. In contrast, we can use 100W to 2000W LED flood light in any outdoor or indoor circumstances! It is widely adopted in football stadium, ice arena and airport! The article is talking about the difference between MH, HPS and LED, as well as answer you the question of should I replace metal halide & high pressure lamps with LED?

1. History of MH, HPS and LED

Metal halide lamp is invented in 1912 (becomes mature in 60s), while high pressure sodium is 1932 and LED is firstly used in 1962. Therefore, we can see LED is a relatively contemporary lamp in lighting field.

2. Working principle comparison

How does metal halide light work? Comparing to LED light that use electric current and electrons to drive the excitation within the semi-conductor, MH lamps need a high voltage arc tube the vaporize mercury vapor and then excite the gaseous chemical to produce light, which is similar to the alumina arc tube inside the HPS. Therefore, you can see that metal halide and high pressure sodium have a very similar working principle – using the ballast to provide sufficiently high voltage for triggering the start of illumination. However, the ballast is not needed as LED can use low voltage to drive the light to turn on, which is more convenient; therefore, it is wise to replace the HPS & MH.

3. Energy & Power efficiency

The luminous efficacy of metal halide vs high pressure sodium is quite similar – having 60 to 110 lumens per watt for MH while 50 to 110 lumens per watt for HPS. If you compare this value to LED of 140 lumens per watt, we can observe that under the same wattage consumption, it produce brighter light and thus save your energy and electricity bill, so why not do high pressure sodium replacement with LED? In fact, much energy is consumed in the ballast to provide the instant high-voltage arc in high-pressure sodium floodlight, the energy percentage waste is about 20 to 40%. Imagine that you have many 250 watt high-pressure sodium lamps. By replacing them at once, you can save much energy.

4. Colors for different applications

Metal halide flood lamps produce white light for large areas while high pressure sodium lights emit yellowish-orange lighting for street. In fact, there are 90% street light still using HPS as the light source because of their availability and good color rendering index, while we can see majority of large area such as warehouse, factory, foundry and sea port high mast lighting are installation MH lamps! Nonetheless, the number of owner seeking for LED replacement for MH and HPS is on the surge. It is because LED is so versatile to produce white or amber lights, while maintaining a good color rendering index, as well as durability. Retrofit the traditional HPS & MH does no harm.

5. Durability among LED, MH and HPS

MH vs HPS have similar life span of 10,000 to 20,000 hours. LED has 80,000 hours life span, if you switch it to year, it is 27 years based on 8 hours operation per day. Besides, it is easy for us to make the LED light becomes waterproof because of its solid-state structure. Short life cycle means the maintenance rate is larger. If you use MH lamps for garage, you may need to replace them for every few months!

Since LED light has many advantages and difference over HPS and MH, it is strongly believed that replacement or retrofit would be very common in near future.